Autonomous Behaviors for a Remove Vehicle

ABSTRACT

A system and method for allowing an operator to switch between remote vehicle tele-operation and one or more remote vehicle autonomous behaviors, or for implementing remote vehicle autonomous behaviors. The system comprises an operator control system receiving input from the operator including instructions for the remote vehicle to execute an autonomous behavior, and a control system on the remote vehicle for receiving the instruction to execute an autonomous behavior from the operator control system. Upon receiving the instruction to execute an autonomous behavior, the remote vehicle executes that autonomous behavior.

This application claims priority to U.S. Provisional Patent ApplicationNo. 60/911,785, entitled “Sliding Autonomous Assist for RoboticPlatforms,” filed Apr. 13, 2007 and U.S. Provisional Patent ApplicationNo. 60/828,632, entitled “Autonomous Robot Behaviors,” filed Oct. 6,2006. This application is a continuation-in-part of U.S. patentapplication Ser. No. 11/739,590 entitled “Control System for a RemoteVehicle,” filed Apr. 24, 2007.

FIELD OF THE INVENTION

The present invention relates to a method and device for simplifyingcontrol of a remote vehicle. The present invention more specificallyrelates to autonomous behaviors for remote vehicles, and moreparticularly to switching between tele-operation of a remote vehicle andautonomous remote vehicle behaviors.

BACKGROUND OF THE INVENTION

Remote vehicles are increasingly being used in military, lawenforcement, and industrial applications to provide a tool for a personto perform operations at a safe, remote distance from sites of potentialdanger or hazard to human beings. Such remote vehicles are beingdeployed for some tasks by military and civilian forces, such as bomband ordnance disposal, in which the remote vehicle is remotely navigatedto the proximity of the explosives or other potentially dangerous targetby an operator located hundred of meters away, so that investigation anddisarmament can take place at a safe distance.

In typical remote vehicle operation, the operator controls the vehicleusing a process known as tele-operation. Conventional remote vehicletele-operation involves the use of operator control consoles, mostcommonly having joysticks, trackballs, mouse-type input devices, or somearrangement of physical switches and/or potentiometers and similarmanual actuation input devices. Remote vehicles are typically configuredwith many axes of motion, including motion drive axes, steering axes(either physical or derived virtual steering), manipulation axes, sensorpan-tilt-zoom axes, etc. The axes of the remote vehicle often involvecomplex mechanical coupling between the drive actuators and the physicalmotion apparatus, such as wheels, tracks, rudders, heads, etc.Additionally, remote vehicle platforms typically contain many sensors,such as cameras, that can provide multiple streams of video to theoperator as visual feedback to aid the operator's control. Theelectromechanical complexity of many remote vehicles has consequentlymade the manual control of such vehicles complex for human operators ina tele-operation process, requiring many function-specific knobs,joysticks and buttons to perform a task. A significant amount ofoperator training and experience can be required to develop sufficientmanual dexterity and skill to be able to accurately navigate and controla remote vehicle.

In order for robots to be beneficial in such activities, a method anddevice are needed to allow remote vehicles to accomplish certainbehaviors autonomously, either continuously or upon user commands.

SUMMARY OF THE INVENTION

The present invention provides a system for allowing an operator toswitch between remote vehicle tele-operation and one or more remotevehicle autonomous behaviors, or for implementing remote vehicleautonomous behaviors. The system comprises an operator control systemreceiving input from the operator including instructions for the remotevehicle to execute an autonomous behavior, and a control system on theremote vehicle for receiving the instruction to execute an autonomousbehavior from the operator control system. Upon receiving theinstruction to execute an autonomous behavior, the remote vehicleexecutes that autonomous behavior.

The remote vehicle executes the autonomous behavior if permitted, andthe autonomous behavior is not permitted if one or more of the remotevehicle's position within its environment, the current internal state ofthe remote vehicle, the current operational behavior of the remotevehicle, or the remote vehicle's environment are incompatible with theautonomous behavior.

The control system includes an arbiter, and the autonomous behaviorsends a vote to the arbiter requesting control of one or more actuatorson the remote vehicle necessary to perform the autonomous behavior. Ifthe voting autonomous behavior has a higher priority than a behaviorcurrently in control of the one or more actuators, the autonomousbehavior executes.

The autonomous behaviors include one or more of ballistic,semi-ballistic, and persistent behaviors. Ballistic behaviors includeone or more of stair climbing, preset actions, click-to-drive,click-to-grip, preconfigured poses, retro traverse, self-righting, andautonomous flipper. Semi-ballistic behaviors include one or more ofquick brake, speed boost, and cruise control. Persistent behaviorsinclude one or more of retro traverse, self righting, obstacleavoidance, and autonomous flippers.

The present invention also provides a method for allowing an operator toswitch between remote vehicle tele-operation and one or more remotevehicle autonomous behaviors, or for implementing remote vehicleautonomous behaviors. The method comprises inputting instructions forthe remote vehicle to execute an autonomous behavior; evaluating one ormore of the remote vehicle's position within its environment, thecurrent internal state of the remote vehicle, the current operationalbehavior of the remote vehicle, or the remote vehicle's environment areincompatible with the autonomous behavior; and allowing the autonomousbehavior to send a vote to an arbiter if the remote vehicle's positionwithin its environment, the current internal state of the remotevehicle, the current operational behavior on the remote vehicle, or theremote vehicle's environment are compatible with the autonomousbehavior. A vote to the arbiter requests control of one or moreactuators on the remote vehicle necessary to perform the autonomousbehavior.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a embodiment of a control system of the presentinvention and a remote vehicle;

FIG. 2 is a top view of an embodiment of a hand-held controller of thecontrol system of the present invention;

FIG. 3 is a rear view of the embodiment of FIG. 2;

FIG. 4 is a side view of the embodiment of FIG. 2;

FIG. 5 is a front sectional view of an embodiment of a roller wheel foruse with the control system of the present invention;

FIG. 6 is a side view of the roller wheel embodiment of FIG. 5;

FIG. 7 is a top view of an embodiment of a rotary ring switch for usewith the control system of the present invention;

FIG. 8 is another top view of the rotary ring switch embodiment of FIG.7;

FIG. 9 is a side view of the rotary ring switch embodiment of FIG. 7;

FIG. 10 illustrates an embodiment of a quick-release pad of the controlsystem of the present invention;

FIG. 11 is an embodiment of a user interface of the control system ofthe present invention;

FIG. 12 is another embodiment of a user interface of the control systemof the present invention;

FIG. 13 illustrates an exemplary use of the control system of thepresent invention with a remote vehicle;

FIG. 13A illustrates an embodiment of the invention including atwo-piece hand-held controller;

FIG. 13B illustrates another embodiment of the invention including atwo-piece hand-held controller;

FIG. 13C illustrates another embodiment of the invention including atwo-piece hand-held controller;

FIG. 14 is a block diagram illustrating an exemplary embodiment ofautonomous behaviors;

FIG. 15 is a flow diagram illustrating an activation routine used toactivate a ballistic behavior and its associated routines;

FIG. 16 is a flow chart illustrating a routine for activating asemi-ballistic behavior used to tune a behavior;

FIG. 17 is a flow chart illustrating a routine to activate orde-activate a persistent behavior;

FIG. 18 illustrates the execution of routines within a persistentbehavior;

FIGS. 19A and 19B illustrate an embodiment of a remote vehicle of thepresent invention;

FIG. 20 illustrates a mobile robot for use with an embodiment of thepresent invention;

FIG. 21 is a block diagram depicting an embodiment of a mobile robotcontrol system;

FIG. 22 illustrates an embodiment of a chassis assembly;

FIG. 23 illustrates an embodiment of a neck module;

FIG. 24 illustrates an embodiment of a head module;

FIG. 25 illustrates an embodiment of a gripper module;

FIG. 26 illustrates an embodiment of a network installed between a head,a neck, a control system, and a chassis;

FIG. 27 illustrates an embodiment of an Ethernet endpoint block;

FIG. 28 illustrates an embodiment of the invention using the Ethernetendpoint block in the chassis, neck, head and EO/IR payload;

FIGS. 29A and 29B illustrate an embodiment of a robotic arm;

FIG. 30 illustrates an embodiment of a behavior system to be includedwithin a remote vehicle;

FIG. 31 illustrates a listing of behaviors within the behavior system inan exemplary order of priority;

FIG. 32 illustrates an embodiment of a stair climbing behavior;

FIGS. 33A and 33B illustrate positions of a remote vehicle relative totarget stairs;

FIG. 34 illustrates an embodiment of a method for performing a stairclimbing behavior;

FIG. 35 illustrates an embodiment of a preset action sequence behavior;

FIG. 36 illustrates an embodiment of a control system display for aclick-to-grip behavior;

FIG. 37 illustrates an embodiment of a click-to-grip routine;

FIG. 38 illustrates an embodiment of a click-to-drive routine;

FIG. 39 illustrates an embodiment of a technique for moving amongpreconfigured poses;

FIG. 40 illustrates another embodiment of a technique for moving amongpreconfigured poses;

FIG. 41 illustrates an embodiment of a waypoint routine;

FIG. 42 illustrates an embodiment of a retro traverse behavior;

FIG. 43 illustrates an embodiment of remote control operation of aremote vehicle in an urban combat zone;

FIGS. 44A and 44B illustrate a retro traverse behavior;

FIGS. 45A-45C illustrate a retro traverse behavior;

FIGS. 46A-46D illustrate a retro traverse behavior;

FIG. 47 illustrates a retro traverse behavior;

FIGS. 48 and 49 illustrate an embodiment of speed boost and quick brakebehaviors;

FIG. 50 illustrates an embodiment of a cruise control routine includedwithin a cruise control behavior;

FIGS. 51A and 51B illustrate an embodiment of a cruise control behavior;

FIG. 52 illustrates an embodiment of a flow of information in a cruisecontrol behavior;

FIG. 53 illustrates an embodiment of a routine to generate cruisecontrol commands;

FIG. 54 illustrates an embodiment of an interaction between a cruisecontrol behavior and other behaviors;

FIGS. 55A-55D illustrate an embodiment of an interaction between acruise control behavior and an obstacle avoidance behavior; and

FIG. 56 illustrates an embodiment of an obstacle avoidance routine foran obstacle avoidance behavior.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

An embodiment of a control system (also called an “operator controlsystem” herein) for use with the present invention includes anunobtrusive, highly mobile control system that provides the user with aremote vehicle operating experience that seamlessly integrates with theuser's other tasks and duties. The control system allows the user toinitiate autonomous behaviors for the remote vehicle, and to switchbetween tele-operation and such autonomous behaviors. Situationalawareness is minimally compromised when operating the system, as it iscritical for the user to be aware of his surroundings. Basic componentsof the control system, which are illustrated in FIG. 1, include adisplay, an input device, a processor, an antenna/radio (for wirelesscommunication), and software. In an embodiment of the invention, ahead-mounted display provides video display from one or more remotevehicle cameras. A hand-held controller, preferably having a twin-gripdesign, includes controls to drive, manipulate, and monitor the robotand its payloads. Audio may additionally be provided via the hand-heldcontroller, the display, or dedicated listening devices such as, forexample, Bluetooth headsets commonly used with mobile phones. In anembodiment of the invention, a microphone is provided on the hand-heldcontroller, the processor, the display, or separately from thesecomponents, and can be used with a speaker on the remote vehicle tobroadcast messages. A button on the hand-held controller or a softbutton within the GUI can be used to activate the speaker and microphonefor broadcasting a message.

The system is preferably compatible with MOLLE packs, ALICE packs,ILBEs, or OTVs commonly worn by users. The system preferably has thefollowing additional characteristics: lightweight (e.g., no more than 7pounds total, and no more than 2 pounds for the hand-held controller);mobile; small form factor (e.g., able to integrate with existing usergear); wearable or capable of being carried in a backpack; easy to puton/take off; adequate computer processing power; minimal or no externalcables; meets mission time thresholds (e.g., 5 hours); rugged tointended environment (e.g., temperature, shock, vibration, water, etc.);able to withstand being dropped (e.g., 3 feet).

The platform should have standard interfaces for networking, display,wireless communication, etc.

The control system, as illustrated in FIG. 1, includes a processor suchas a rugged laptop computer. The processor could alternatively be anysuitably powerful processor including, for example, a tablet PC. Theprocessor communicates with the remote vehicle wirelessly or via atether (e.g., a fiber optic cable). Although wireless communication maybe preferable in some situations of remote vehicle use, potential forjamming and blocking wireless communications makes it preferable thatthe control system be adaptable to different communications solutions,in some cases determined by the end user at the time of use. A varietyof radio frequencies (e.g., 802.11), optical fiber, and other types oftether may be used to provide communication between the processor andthe remote vehicle.

The processor must additionally communicate with the hand-heldcontroller and the display. In a preferred embodiment of the invention,the processor is capable of communicating with the hand-held controllerand the display, illustrated in the present embodiment to be ahead-mounted display, either wirelessly or using a tether. To facilitatewireless communication among the various elements of the system, theprocessor includes a radio and an antenna.

It addition, the processor includes software capable of facilitatingcommunication among the system elements, and controlling the remotevehicle. In an embodiment of the invention, the software is aproprietary software and architecture, including a behavioral system andcommon OCU software, which provide a collection of software frameworksthat are integrated to form a basis for robotics development. Accordingto an embodiment of the invention, this software is built on acollection of base tools and the component framework, which provide acommon foundation of domain-independent APIs and methods for creatinginterfaces, building encapsulated, reusable software components,process/module communications, execution monitoring, debugging, dynamicconfiguration and reconfiguration as well as operating system insulationand other low-level software foundations like instrument models, widgetlibraries, and networking code. In an embodiment of the invention, theprocessor performs all of the data processing for the control system.

Referring to FIG. 2, an exemplary embodiment of a twin-grip hand-heldcontroller is illustrated. The hand-held controller includes left andright grips shaped to be held between a little finger, a ring finger,and the ball of a thumb of a respective hand, leaving the index finger,middle finger, and thumb of the respective hand free to manipulatecontrols. Two joysticks (analog, having 4 degrees of freedom) areprovided on the left and right sides of the hand-held controller. Thejoysticks may be 2-axis analog. In an embodiment of the invention,analog-to-digital resolution of the joysticks is at least 12-bit peraxis with the joystick center “dead band” (maximum offset from center onspring return) being less than about 3% of total resolution. If pressed,the joysticks can function as digital buttons. The present inventionalso contemplates using pucks (6 degrees of freedom) instead ofjoysticks.

In an embodiment of the invention, the left joystick is commonly used todrive the remote vehicle (forward, backward, left, and right). The rightjoystick controls one or more other functions of the robot depending ona selected button function mode, including a camera (e.g., the attackcamera), a weapon, or flipper control.

A directional pad is located on a left side of the hand-held controllerand includes an array of four or five discrete digital buttons formanipulation by the user's left thumb. The buttons are arranged in adiamond shape with an optional button in the center. The four buttonsnot in the center preferably come to a rounded point at one end toindicate direction. One button points up, one points down, one pointsright, one points left. In an embodiment, the four buttons not in thecenter have a generally flat exposed surface and the center button has agenerally hemispherical exposed surface and is raised above thesurrounding buttons. In an embodiment of the invention, the directionalpad is used to navigate among the soft buttons of a GUI displayed by thehead-mounted display. The center button of the array, when present, maybe used to select a soft button of the GUI.

A right button array includes an array of four discrete digital buttonsfor manipulation by the user's right thumb. The buttons are arranged ina diamond shape and are circular with exposed surfaces that may be atleast slightly curved. The right button array can be used to control avariety of functions such as camera selection, robot light setting, androbot speed. When no center button is provided on the directional pad,one of the buttons of the right button array may be used to select asoft button of the GUI.

A center button array is shown to include five discrete digital buttonsfor manipulation by the user's thumbs. A first button is generallylocated in an upper left region of the center area, a second button isgenerally located in an upper right region of the center area, a thirdbutton is generally located in a lower left region of the center area, afourth button is generally located in a lower right region of the centerarea, and a fifth button is generally located in the center of the otherbuttons. The first four buttons are elongated (generally rectangular)and the fifth button is generally hemispherical. In an embodiment of theinvention, the center button is larger than the other buttons in thecenter array.

In an embodiment of the invention, the upper right button (second)button is the menu button, which brings up a menu within the GUIdisplayed by the head-mounted display. The menu is preferably ahierarchical menu, such as a drop-down menu, that allows the user toselect a screen layout, a robot to control, select a safe mode for therobot (such as observe mode), manage and play video, audio and snap shotrecordings, select among other settings such as brightness, andtime/date, or review documentation regarding the controller or therobot. In this embodiment, the upper left (first) button acts as a pauseor brake button for the robot, ceasing movement of the robot untilreleased. To prevent accidental activation, the pause/brake button maybe recessed and/or may require a minimum force for activation.

A button on the hand-held controller or a soft button within the GUI canbe used to switch controllers, so that another hand-held controller oralternative control device can take over control of the remote vehicle.This can allow multiple operators to control the same remote vehicle.

The pause or brake button may alternatively be designed as a dead man'sswitch to ensure safe operation of the robot—if the user's finger isreleased from the switch, the robot ceases to operate. In an embodimentof the invention, the dead man's switch is located under the user's leftindex finger, right index finger, left middle finger, or right middlefinger.

Bumper or rocker buttons are located on the shoulders of the hand-heldcontroller, the buttons making up a rocker control. Two rocker buttonsmake up a first rocker control on the left shoulder and are orientedvertically, and two more rocker buttons make up a second rocker controlon the right shoulder and are also oriented vertically. As analternative to rocker buttons, one-axis switches may be provided on theleft and right shoulders (not shown). The rocker buttons, being alignedvertically along the shoulder of the hand-held controller, are therebylocated in a pitch plane parallel to the articulated flipper drive. Inan embodiment of the inventions, the rocker control on the rightshoulder is used for flipper control.

The directional pad, left joystick, and left shoulder rocker controlmake up a left control zone. The right button array, right joystick, andright shoulder rocker control make up a right control zone.

A power button is located between the left and right shoulder areas ofthe hand-held controller. In the illustrated embodiment, the button iscircular with a flat protruding surface. The button may optionally berecessed (to prevent inadvertent actuation) and/or backlit with an LEDthat indicates the state of the hand-held controller (i.e., on or off).In an embodiment of the invention, the area of the hand-held controllerimmediately surrounding the power button is smooth to facilitate usingelectrical tape to cover the power button and its LED as needed.Covering the power button can avoid detection of the hand-heldcontroller. The power button on the hand-held controller may control thestate of just the hand-held controller, or of a number of other systemcomponents, such as the processor and one or more displays (e.g., thehead-mounted display).

An embodiment of the invention includes a tether zone (see FIG. 3)located between the left control zone and the right control zone, whichincludes a tether anchor configured to tether the hand-held controllerbetween the left grip and right grip and permit the hand-held controllerto hang in use (see FIG. 13) with the left grip and right grip pointingupward. A tether, or cord, extends from the tether anchor, preferably tothe right shoulder of a dismounted operator.

In an embodiment of the invention, the tether is detachable from thehand-held controller, and connects the hand-held controller to theprocessor for non-wireless communication between the two. In anembodiment of the invention, the hand-held controller can operate onbattery power and communicates wirelessly with the processor, but hasthe ability to accept a tether when non-wireless connection ispreferred.

In an embodiment of the invention, the tether has a strain reliefallowing it to be flexible but also physically support the weight of thehand-held controller and withstand being dropped the a distance equal tothe tether's length (e.g., 3 feet) without damage or disconnection.

In an embodiment of the invention, the tether attaches to the hand-heldcontroller via an environmentally sealed connector, such as push-pull,screw latching, etc. The same environmentally sealed connection may beused where the tether connects to the processor. The tether connectorsmay be keyed to prevent pin misalignment during connection.

FIGS. 5 and 6 illustrate an optional roller wheel that may be providedon the hand-held controller. In an exemplary embodiment, the rollerwheel is surrounded by a textured tire and sits in a cavity of thehand-held controller. The cavity is formed in the exterior surface ofthe hand-held controller and includes an interior shell to encase theroller wheel. An axle extends between two sides of the interior shelland allows the roller wheel to rotate within the cavity. Bushings mayadditionally be provided to reduce friction and wear. The axle extendsinto a rotary transducer located on at least one side of the cavity, therotary transducer measuring rotation of the roller wheel and convertingit to a digital output. The location of the roller wheel on thehand-held controller, if provided, may vary, although the wheel ispreferable located so that it can be actuated by the user's thumb orforefinger (either left or right). The roller wheel may be used, forexample, for camera zoom or to scroll among soft buttons in the GUI.

FIGS. 7, 8, and 9 illustrate an optional rotary ring switch. In theillustrated exemplary embodiment, the rotary ring switch is locatedaround a joystick and includes three positions on the ring that may beselected by sliding a selector along the ring to one of the positions.In an embodiment of the invention, the rotary ring switch surrounds theleft joystick so that selection is made with the user's left thumb. Therotary ring switch may be used to select among button functions modes.

The present invention contemplates a variety of locations for the ringswitch if one is provided, as well as a varying number of positions forselection. For example, the ring switch could surround the rightjoystick, the directional pad, the right button array, or the centerbutton array.

The present invention contemplates using labels (not shown) on or nearthe buttons of the hand-held controller to indicate the functionality ofone or more of the buttons.

It will be appreciated by those skilled in the art that location andshape of the buttons may vary among embodiments of the invention. Thepresent invention contemplates a variety of button shapes and locations.Additional buttons may be added, or buttons may be removed within thescope and spirit of the invention.

The present invention contemplates additional or alternativefunctionality for the hand-held controller. For example, the hand-heldcontroller may be able to detect aspects of its own movement viaaccelerometers and gyroscopes and translate that movement into remotevehicle control functions such as, for example, scrolling through a GUImenu. While the hand-held controller's movement could be translated intocorresponding movement of the remote vehicle, such control may not beadvisable in certain situations where precise control of the remotevehicle is critical and/or the controller may be subject to unforeseenjostling with potentially hazardous results in terms of correspondingmovement of the remote vehicle.

An embodiment of the invention provides mode changing software forchanging button mapping of the hand-held controller between, forexample, driving a robot, manipulating an arm, controlling a camera,etc.

In an embodiment of the invention, switching among button function modesof the hand-held controller is accomplished by actuating a button ortoggle-type switch, preferably using the operator's index finger(s).This can be accomplished using an above-described rotary ring switch,another button on the hand-held controller, or even the optional rollerwheel described above. The present invention also contemplates switchingbutton function modes on the left side of the controller which oneswitch or button, preferably located on the left side, and switchingbutton function modes on the right side of the controller which anotherswitch or button, preferably located on the right side.

According to an embodiment of the invention, button function modesinclude:

Drive Mode—the left joystick is used to steer the robot forward, back,left, and right, the left button array is used to control the attackcamera (for a robot having, for example, a drive camera and an attackcamera), the right joystick controls a spooler (for example containingfiber optic cable), the right button array controls a variety offunctions such as the camera zoom, robot lights, robot speed, an camerachoice (allows user to choose one or more cameras as, for example,primary and secondary), and the right shoulder is for flipper control.

Manipulate (Gripper) Mode—the left joystick is used to move the gripperforward, back, left, and right, the right joystick is used to move thegripper up and down and to fold or unfold the elbow, and the rightshoulder buttons are used to rotate the gripper clockwise andcounterclockwise.

Target (Attack Camera) Mode—The left joystick is used to move the attackcamera forward, back, left, and right, and the right joystick is used tomove the attack camera up and down.

Joint Mode—The left joystick folds and unfolds the gripper shoulder(e.g., using the top and bottom buttons), and rotates the turretclockwise and counterclockwise (e.g., using the right and left buttons).The right joystick folds and unfolds two gripper elbows. The left buttonarray controls the attack camera, and the right button array controls avariety of functions such as the camera zoom, robot lights, robot speed,and camera choice. The right shoulder buttons are used to rotate thegripper clockwise and counterclockwise.

Menu (GUI Navigation) Mode—The left joystick navigates a cursor up,down, right, and left, the left button array moves the menu itself up,down, left, and right, and the right button array includes cancel andselect functions.

Among the above exemplary button function modes, certain buttons maymaintain the same functions, such as the top left button of the centerbutton array being a pause/brake button, and the top right button of thecenter button array being a menu button. In addition, the button tochange among the above functional modes may remain the same. In anembodiment of the invention, the left joystick is always used to drivethe remote vehicle and the directional pad is always used to navigatesoft buttons of the GUI. It is the other buttons that changefunctionality among modes.

It should be understood that the present invention contemplates avariety of button mapping scenarios, and a variety of single andcombined function modes that allow the operator to control one, two, ormore payloads of the remote vehicle with the same hand-held device bymanipulating the buttons on the hand-held controller.

In an embodiment of the invention, the weight of the hand-heldcontroller, including the cord, is less than or equal to two pounds. Ina preferred embodiment, the weight of the hand-held controller itself isless than one pound, and the dimensions are no larger than4.5″×2.5″×6.5″.

According to an embodiment of the invention, the hand-held controller isruggedized. For example, the casing and switch plate may comprisealuminum, and the unit or parts thereof may be coated in plastisol oranother suitable coating. In addition, the tether connection may beenvironmentally sealed, and the buttons may additionally be madewaterproof as is know to those skilled in the art, particularly in thearea of waterproof cameras.

For adhering the hand-held controller to the user's gear, an embodimentof the invention includes a quick-release system. An embodiment of thequick-release system includes a quick release pad, an embodiment ofwhich is illustrated in FIG. 10. The quick-release pad preferablycomprises Velcro® on an outer-facing side thereof, and has a sizesuitable to allow releasable but stable attachment of the hand-heldcontroller to the pad. The pad is attached to a loop on the user's gear.In the embodiment of FIG. 10, the loop is a horizontal loop such asthose provided on an OTV. A strap connected to the quick-release padcircles through the OTV loop to attach the quick-release pad to the OTV.An additional quick-release mechanism (not shown) may be used toreleasably fasten the tether (which connects the hand-held controller tothe processor) to the user's gear. Complementary material is located onan underside the hand-held controller to mate with the quick-releasepad. In an embodiment of the hand-held controller including protrusionsextending from a bottom thereof (see FIGS. 3 and 4), the complementarymaterial is located on the protrusions. In an alternate embodiment with,for example, a flat bottom, at least a portion of the bottom wouldinclude complementary material. Because Velcro® can wear out and becomeless effective, the present invention contemplates the Velcro in thequick-release system being easily replaceable.

The head-mounted display illustrated in FIG. 1 generally indicates adisplay device worn on a user's head or as part of a helmet, which has adisplay optic in front of one or both eyes. A typical head-mounteddisplay has one or two displays with lenses and semi-transparent mirrorsembedded in a helmet, eye-glasses, or a visor. The display units areminiaturized and may include cathode-ray tubes (CRTs), liquid crystaldisplay (LCD), Liquid Crystal on Silicon (LCos), or an organiclight-emitting diode (OLED).

The head-mounted display allows the remote vehicle operator to see whatthe remote vehicle sees through one or more cameras, so that the remotevehicle can be controlled when it is not within the operator's line ofsight, and also allows the operator to maintain situational awareness.In an embodiment of the invention, the head-mounted display is an Icuititactical display.

The head-mounted display displays a GUI with views from the robot'scamera(s) and information about the robot such as battery life,payloads, communication status, etc., and also displays soft buttonsthat are mapped to the hand-held controller buttons and allow the userto more intuitively control the robot using the hand-held controller.

The present invention contemplates using one or more head-mounteddisplays with a single control system. In addition, the video streamfrom the robot camera(s) can be multi-casted for use by multipleclients. Indeed, the multiple clients need not only be multiplehead-mounted displays, but may alternatively or additionally include avariety of displays and/or recoding devices in a variety of locations.

The head-mounted display is preferably capable of either wireless ortethered communication with the hand-held controller through theprocessor.

As stated above, a menu mode of the hand-held controller allows the userto navigate among soft buttons or icons displayed by the head-mounteddisplay. Exemplary embodiments of the GUI display are illustrated inFIGS. 11 and 12.

As illustrated in the embodiment FIG. 11, the head-mounted displayprovides the user with a variety of information in what is indicated asa “max camera” layout. In this illustrated embodiment, the main image isa video stream from the robot's attack camera and the smaller image inthe lower right corner is video stream from the robot's drive camera. Asan alterative to video streams, a series of snapshots can be displayedat predetermined time intervals. The status of the attack camera (e.g.,front zoom) is displayed in the upper left corner, and certain cameracontrol icons or soft buttons are presented under the camera status. Inthis embodiment, the icons include zoom in, zoom out, IR filter on/off,IR light off/low/medium/high, camera default position (designated inthis embodiment as a V in a sun shape), camera setting choices, audiochoices, snap shot, and video record on/off. In this embodiment, uponchoosing (by pressing the soft button or icon by manipulating thehand-held controller in the menu mode) camera settings and audio, theGUI pops up a screen to select among a variety of setting options. In anembodiment of the invention, the icons can be minimized. Above thestatus of the camera, the robot's name can be displayed (illustratedherein as “Name567890123456”).

The camera may be returned to its default position, or otherwisecontrolled, via the soft button mentioned above, or a button on thehand-held controller.

Additional icons or soft buttons may be displayed, for example on theright side of the head-mounted display view. In this embodiment, theicons or soft buttons include, from top to bottom, status ofcommunication link (with robot), battery charge level (of the robot andthe OCU), speed toggle (wherein the snail icon indicates that the robotis in a slow range of speed within the available scalable range ofspeed), robot heading, two icons indicating the robot's position andheading, and a variety of autonomous assist options such as predefinedposes (described in detail below).

Another embodiment of the system's GUI, indicated as a “quad” layout, isillustrated in FIG. 12. The larger, upper left image is a video streamfrom the robot's attack camera and the smaller image in the center ofthe display is video stream from the robot's drive camera. As analterative to video streams, a series of snapshots can be displayed atpredetermined time intervals. The status of the attack camera (e.g.,front zoom) is displayed in the upper left corner, and certain cameracontrol icons or soft buttons are presented under the camera status, asset forth for the prior embodiment. In an embodiment of the invention,the icons can be minimized. Above the status of the camera, the robot'sname can be displayed (illustrated herein as “Name567890123456.” Underthe camera controls is a map icon allowing the user to select additionalinformation from the system's mapping function. To the right of the mapicon and under the video stream from the attack camera, mappinginformation regarding one or more of the robot's prior mission movementscan be displayed. Alternatively, the missions of a number of nearbyrobots are displayed.

Additional icons or soft buttons may be displayed, for example on theright side of the head-mounted display layout. Similar to the previousembodiment, the icons or soft buttons include, from top to bottom,status of the communication link (with robot), battery charge level (ofOCU), speed toggle wherein the snail icon indicates that the robot is ina slow range of speed (within the available scalable range of speed),and a variety of autonomous assist options such as predefined poses. Inthis embodiment, the poses are indicated by name rather that a graphicalrepresentation of the pose itself. Payload icons under the pose iconsallow the user to activate a payload or bring up a control menu for thatpayload. They can also display information regarding selected payloads.Possible payloads include cameras, chemical detection devices, sniperdetection devices, cable spools, batteries, etc. In the illustratedembodiment, payload 3 is an Explorer extension added to the chassis ofthe robot, and payloads 4 and 5 are batteries.

To the right of the video stream from the robot's attack camera is arepresentation of the robot's position and heading, including any tilt.Under the positional representation is an identification of the payloadsand information regarding the payloads, such as an indication ofremaining battery life.

In accordance with the present invention, the user may choose among avariety of GUI layouts, such as the “max camera” and “quad” layoutsdescribed above.

In the above illustrative embodiments of the GUI, the icons or softbuttons may be displayed continuously for the user, who navigates amongthem using a dedicated set of buttons on the hand-held controller (e.g.,the directional pad), or may be displayed only when the hand-heldcontroller is in a menu mode. Additional soft icons or buttons may bedisplayed as desirable. In an embodiment of the invention, theillustrated icons are displayed continuously for the user, and selectionof a menu mode on the hand-held controller brings up an additionalhierarchical menu of functions through which the user can navigate, forexample, using the directional pad.

In an embodiment of the control system of the present invention, audiois provided on one or more of the processor, the hand-held controller,the head-mounted display, or a separate headset.

The control system of the present invention preferably has two states(on and off) and three modes: (1) training mode; (2) operation mode; and(3) maintenance mode. The modes of the control system are distinct fromthe button function modes of the hand-held controller. After beingpowered on, the system may default into an operation mode, default tothe last mode selected, or may initially prompt the user to choose amongthe three modes. Most system functions, including the exemplaryfunctions listed in the table below, are preferably performed in allthree modes.

Power On/off Status Communicate communicate with robot status ofcommunications tethered and wireless communication Control drive/stopbrake engage/release speed control flipper control head/neck controlpose selection camera selection camera zoom camera control optionsincluding aperture/exposure/resolution/black and white/color/etc.microphone control on/off/speak speaker control on/off/volume requestinformation/status/data illumination on/off/other select options selectrobot payload control map controls (autonomous robots or assistance)autonomy controls Display display video display health and status(system) display options GPS location/navigational information AudioEmit Send adjustment options Process process data/audio/video

The system is intended for use by a dismounted operator, dismountedmeans that the operator is freely moving about outside of the remotevehicle(s). However, the system may additionally be used by an operatorthat is not dismounted. The system of the present invention may beuseful to an operator that is not dismounted in an instance where theoperator has difficulty reaching all of the controls needed to operatethe vehicle and its payloads, or the vehicle and other remote vehicles.

The system of the present invention should be capable of controllingremote vehicle mobility, executing operator tasks with one or moreremote vehicles, and supporting maintenance functions.

FIG. 13 illustrates a soldier using the control system of the presentinvention to control a robot. Although the robot is illustrated to be inthe soldier's line of sight, the present invention is directed tonon-line-of-sight operation as well, with the solder using thehead-mounted display to see what the robot sees and thereby effectivelycontrol the robot.

FIG. 13A illustrates an embodiment of the invention including atwo-piece hand-held controller that functions substantially similar tothe one-piece hand-held controller described above. This embodiment ofthe invention allows the left portion of the controller to be attachedto the user's gun, so that one hand can remain on the gun whilecontrolling the remote vehicle.

FIGS. 13B and 13C illustrate another embodiment of the inventionincluding a two-piece hand-held controller. In this embodiment, theright hand controller is mounted to the gun and the left hand controllercan be secured to a quick-release pad. The left hand controller wouldpreferably hang from the user's left shoulder. This embodiment would bepreferably where a user is trained to or tends to keep his firing handon the gun.

The controller may have a variety of shapes and sizes to facilitate easeof gripping and actuation by a user. For example, the one or both piecesof the controller may include a grip portion shaped to be held between alittle finger, a ring finger, and the ball of a thumb of a respectivehand, leaving the index finger, middle finger, and thumb of therespective hand free to manipulate controls. One or both pieces of thecontroller may include a joystick t be manipulated by the user's thumb.The two-piece hand-held controller may include the same number ofbuttons as the one-piece controller above, or may include a more limitednumber of buttons.

In an embodiment of the two-piece hand-held controller, the two piecesmay be mated to form a one-piece hand-held controller for use asdescribed above. In this embodiment, the two pieces may look more likehalves of the one-piece hand-held controller illustrated in FIG. 2.

As in the prior disclosed embodiments, the hand-held controllercommunicates with the display via a processor (not shown).

Remote vehicles can utilize a number of autonomous behaviors that can beimplemented automatically or via the control system, such as via the GUIicons described above. Such behaviors, illustrated in FIG. 14, can becategorized as: (1) ballistic behaviors that autonomously execute oncewithin a defined operating period; (2) semi-ballistic behaviors thatexecute once within a defined operating period and that operateautonomously while allowing for manual control during execution; or (3)persistent behaviors that execute continuously and autonomously whileallowing the operator to manually control other behavior(s) of theremote vehicle. In an embodiment of the present invention, theautonomous behavior(s) may begin by either responding to sensor outputand autonomously starting the behavior, responding to operator input viathe depression of a key, soft key, or other actuator included thecontrol system described above, or by responding to other behavioroutput.

An embodiment of the present invention provides the operator withvarying levels of autonomy so that the operator may control the remotevehicle at times and choose to allow the remote vehicle to operateautonomously at times or concurrently. Autonomous behaviors that executeone-time operations simplify operator manipulation of the remote vehiclewhen such operation includes monotonous or difficult tasks.

FIG. 14 is a block diagram illustrating an exemplary embodiment ofautonomous behaviors available to an operator and included within theremote vehicle's control system. Included within the control systemmanipulated by the operator is a software array of behaviors organizedunder a main autonomous behavior 7050 and fanning out into the varioussubtypes of autonomous behavior. In particular the main autonomousbehavior 7050 identifies in memory three main subtypes of behaviors:ballistic behaviors 7065, semi-ballistic behaviors 7092 and persistentbehaviors 7053. An embodiment of the present invention includes thecapability to provide all three types of behaviors, but the presentinvention also contemplates providing only one or two types ofbehaviors. Ballistic behaviors 7065 comprise a particular behaviorroutine that executes for a finite period of time when the behavior isactivated. Activation of a ballistic behavior 7065 causes thatparticular behavior's status to indicate that the behavior is active,and further causes that behavior to put in a vote to the actuator togain control of its associated actuators. Exemplary ballistic behaviors7065 include: stair climbing 7068, preset action sequence 7071,click-to-drive or click-to-grip 7074, custom pose presets 7077,autonomous flipper routine 7078, retro traverse 7080, and self-righting7083.

FIG. 15 is a flow diagram illustrating an activation routine used toactivate a ballistic behavior and its associated routines. To activatethe behavior, the operator must actuate a control system button, switch,etc. to generate an associated signal, and the signal is transmitted 802to the control system. The control system then calculates a command 804representative of the actuated button, switch, etc. and sends thecommand to the remote vehicle via a communication connection. Once thecommand is received by the remote vehicle, the remote vehicle's controlsystem 1155 (see FIG. 21) executes a routine to determine if thebehavior is compatible 806 with the remote vehicle's current state. Thismeans that the executed routine will evaluate all sensor output todetermine whether or not the remote vehicle's position within itsenvironment, the current internal state of the remote vehicle, thecurrent operational behavior on the remote vehicle, or the remotevehicle's environment are incompatible with the chosen behavior. If thebehavior is not okay to run (not permitted), the remote vehiclegenerates feedback information 808 that is sent to the user, alertingthe user to the behavior's incompatibility. The ballistic behavioractivation routine is then exited 824.

If the behavior is compatible (permitted), the remote vehicle changesthe start condition of the chosen behavior to a positive value 810,causing the behavior to turn on. Once turned on, the behavior sends avote to the arbiter 812 requesting control of its associated actuators.If the behavior has a higher priority than the behavior currently incontrol of the actuators 814, the remote vehicle will gain control ofthe actuators and wait for a second start condition (explained furtherbelow). If the behavior doesn't have a higher priority than the behaviorcurrently in control of the actuators 814, the behavior will wait 816,and send another vote 812 to the arbiter. The behavior will continue todo this until it gains control of the actuator. Should the behavior havecontrol of the actuator, and its second start condition is true 818,then the software routines included within the behavior will execute822. When finished executing, the routines will alter the behavior'sstart conditions to a false or stop status effectively halting thebehavior 824.

If the remote vehicle's second start condition 818 is not true, thebehavior will wait 820 until such a condition is true. A second startcondition check 818 is included to accommodate those behaviors that maybe in a perpetual start mode, but that are not activated until theyreceive particular sensor information. Alternatively, the second startcondition check 818 could be used to activate routines within behaviorsthat are currently in an “on” state. An example of the above routineincludes starting the stair climbing behavior which can be accomplishedby, for example, depressing a soft button included on the screen, whichin turn creates 800 and sends 802 a signal to the control system. Thecontrol system interprets the signal as indicating the start of stairclimbing, and creates and sends a command 804 to the remote vehicleindicating that the stair climbing behavior should be activated. Aroutine within the remote vehicle's control system 1155 then determineswhether or not the remote vehicle is able to execute stair climbing 806.

In response to an allowance of execution of stair climbing, the routinewill then alter the stair climbing behavior's first start condition 810to a positive or true value and the stair climbing behavior will beginto send votes to the arbiter requesting control over the drive motors,tilt sensor, and other actuators and circuits involved in stairclimbing. When the arbiter determines that stair climbing has thehighest priority 814, stair climbing will then check to see if itssecond start condition is true. Such a start condition could includesuch input as the positioning of a target location over the stair caseusing a selection graphic included on the display screen. Once thetarget location is input, a message could be sent to the remote vehicleindicating that the second start condition is true 818 and furthercausing the routines within the stair climbing routine to execute 822.During the time period between gaining actuator control and realizing asecond start condition, the stair climbing behavior will wait 820. Oncethe robot has reached the top of the stairs, as indicated by the tiltsensor, an end condition is reached and the stair climbing behaviorresets its flags to a stop or negative start condition which effectivelyhalts and stops 824 the stair climbing behavior.

Activation of a semi-ballistic or interactive behavior 7092, on theother hand, can cause one of either an alternative version of apre-existing behavior to execute, or a one-time tuning behavior toexecute. For example, a behavior or routine that starts afire-and-forget process for a limited time (or stopped by a particulardetection) but that permits user interaction or partial tele-operationduring its course (in contrast to what is referred to herein as a“ballistic” behavior, which generally proceeds for a specific timeperiod or until finished but would be interrupted and terminated bytele-operation intervention. Similar to ballistic behaviors 7065,alternative embodiments of the invention can include more or lesssemi-ballistic behaviors in the semi-ballistic set, or can not include asemi-ballistic behavior set 7092 within the autonomous behaviors 7050.Semi-ballistic behaviors 7092 may include, for example, quick brake 7089and speed boost 7086. In an embodiment where the semi-ballistic behavior7065 is used to fine tune another behavior, the behavior chosen to befine tuned can either be selected by the operator via pressing a button,selecting a behavior on the display via soft keys, a mouse, orcontroller, or there could be a behavior pre-associated with aparticular semi-ballistic behavior. Fine tuning a behavior preferablyincludes altering calculations within a routine included within abehavior, or altering variables included within the behavior.

FIG. 16 is a flow chart illustrating a routine for activating asemi-ballistic behavior used to tune a behavior. To activate thebehavior, the operator actuates a control system button or switch, whichgenerates a signal associated with that particular button or switch 830.The signal is transmitted 832 to the control system, which calculates acommand 834 representative of the actuated button or switch and sendsthe command to the remote vehicle via a communication connection. Thiscommand includes information indicating that the semi-ballistic behaviorshould be activated, along with information indicating which behaviorthe semi-ballistic behavior should be applied to. Once the command isreceived by the remote vehicle, its control system 1155 executes aroutine to determine if the behavior is compatible 836 with the remotevehicle's current state. This means that the executed routine willevaluate all sensor output to determine whether the remote vehicle'sposition within its environment, its current internal state, its currentoperational behavior, or its environment are incompatible with thechosen behavior.

If the behavior is not okay to run (not permitted), the remote vehiclegenerates feedback information 838 that is sent to the user, alertingthe user to the behavior's incompatibility, and the ballistic behavioractivation routine is exited 850. Should the behavior be compatible(permitted), the remote vehicle changes the start condition of thechosen behavior to a positive value 840, effectually causing thebehavior to turn on. Once turned on, the behavior sends a vote to thearbiter 842 requesting control of its associated actuators. If thebehavior has a higher priority than the behavior currently in control ofthe actuators 844, then the remote vehicle will gain control of theactuators. If the behavior doesn't have a higher priority than thebehavior currently in control of the actuators 844, then the behaviorwill wait 846, and send another vote 842 to the arbiter. The behaviorwill continue to do this until it gains control of the actuators. Oncethe behavior has control of the actuator, the routine within thebehavior 848 will execute.

The routine selects the chosen behavior to be altered and tune variablesor routines included within the behavior according to the routine withinthe semi-ballistic behavior. Once the routine within the semi-ballisticbehavior finishes altering the chosen behavior, the routine alters thesemi-ballistic behavior's start conditions to a false or stop status,effectively halting the semi-ballistic behavior 824. An example of asemi-ballistic behavior is the speed boost behavior 7086 which has achosen behavior already associated with it, the drive behavior. When anoperator actuates the button or switch associated with speed boost, asignal is created 830 and sent 832 to the control system, where thesignal is converted into a command that is sent to the remote vehiclevia a communication link 834. Once the remote vehicle's control system1155 receives the command, a routine included in the remote vehicle'scontrol system determines whether or not speed boost is compatible withthe remote vehicle's current state. For example, should the remotevehicle currently be climbing stairs, the routine may alert the userthat speed boost cannot be activated. When speed boost is okay toactivate 836, the start condition in the speed boost behavior is set toa positive start value 840, and speed boost begins sending in votes 842to an arbiter (see FIG. 31) to gain control of the actuators associatedwith the drive behavior. Once speed boost is determined to be thehighest priority behavior, the routine within speed boost will thenalter 848 any one of a speed range or velocity value within the drivebehavior. Upon completing the change, the routine within speed boostalters speed boost's start condition to a negative value and the speedboost behavior halts and turns off speed boost 850.

Also included within the autonomous behaviors 7050 are persistentbehaviors 7053, which include behaviors that can be turned on and kepton via an always true first start condition. A persistent behavior isactivated via a proper second start condition. Persistent behaviors 7053start when the remote vehicle is powered up and can be stopped byactuating a control system button, switch, etc. An embodiment of theinvention includes a persistent behavior set 7053 including an obstacleavoidance 7059 behavior. While shown as a semi-ballistic behavior inFIG. 14, cruise control can alternatively be a persistent behavior.

FIG. 17 is a flow chart illustrating a routine to activate orde-activate a persistent behavior. To de-activate a currently activatedpersistent behavior, the operator actuates a control system button,switch, etc. generating a signal that is transmitted 857 to the controlsystem. The control system then calculates a command 859 representativeof the actuated button, switch, etc. and sends the command to the remotevehicle via a communication connection. According to an embodiment ofthe invention, the command either includes a start or stop command thatcauses the persistent behavior to have an on or off state. When on, thebehavior will execute in response to sensor and system input. When off,the behavior will not execute.

Once the command is received by the remote vehicle, the remote vehicle'scontrol system 1155 relays the command to the proper behavior, whichcauses the behavior's first start condition to be altered. When thecommand indicates that the persistent behavior should be turned on, thestart condition will be changed to a positive or on condition. When thecommand indicates that the persistent behavior should be turned off, thestart condition will be changed to a negative or off condition.Depending on whether the condition was made positive or negative, thepersistent behavior will either start or stop 865. In an embodimentwhere persistent behaviors have an initial positive start condition, anoperator will need to turn off the behaviors after the remote vehicle ispowered up to keep the persistent behaviors from executing in responseto system and sensor output.

FIG. 18 illustrates the execution of routines within a persistentbehavior when the routines' second start condition is activated bysystem or sensor output. The flowchart in FIG. 18 assumes that thepersistent behavior's first start condition is true, and has been trueas a function of its “always on” characteristic. To initiate theexecution of the persistent behavior, sensor or system output must besent 867 to the persistent behavior by the remote vehicle's controlsystem 1155. If such output is of the type that will cause the remotevehicle's second start condition to become positive, the persistentbehavior's second start condition flag will be changed 871 to a positiveor start value and the persistent behavior will begin to send votes 873to the arbiter to gain control of the behavior's associated actuatorsand manipulators. If the behavior has a higher priority than thebehavior currently in control of the actuators 873, then the behaviorwill gain control of the actuators. If the behavior doesn't have ahigher priority than the behavior currently in control of the actuators875, then the behavior will wait 878, and send another vote 873 to thearbiter. The behavior will continue to do this until it gains control ofthe actuators or manipulators. Should the behavior have control of theactuator, the routine within the behavior will execute 879. The routinewill continue to execute until it loses control over the actuators 885,in which case one of the first or second start condition flag is changedto a negative or stop value 887 which causes the behavior to stop 883.If the first start condition flag changes to a negative or stop value,the behavior is disabled. In an embodiment of the invention, thebehavior can thereafter be restarted using the routine displayed in FIG.17. If the second start condition flag is changed to a negative or stopvalue, the behavior will stop until it detects sensor or system outputthat causes the behavior to start again.

An example of a persistent behavior is obstacle detection (avoidance)7059, which is always on unless an operator actuates a control systembutton, switch, etc. for altering the first start condition of theobstacle detection behavior. When actuated, a signal is generated andsent 857 to the control system, where a representative command is sent859 to the remote vehicle. Once received by the remote vehicle, thecommand is relayed to the obstacle detection behavior where it changesthe first start condition flag 861 to a negative value. This change ofvalue causes the obstacle avoidance behavior to be disabled. If theobstacle detection behavior remains on, and a sensor detects anobstacle, the sensor output is sent to the obstacle detection behavior867, where it causes the obstacle detection behavior's second startcondition flag to change to a positive or on state 871. Upon the secondstart flag's change in state, the obstacle detection behavior sendsvotes 873 to the arbiter to gain control of the drive assembly,actuators, and assemblies needed to avoid obstacles. When the arbiterdetermines that obstacle detection has the highest priority 875,obstacle detect then executes it routines 879. While executing, thebehavior checks to make sure that it has control of the actuators 885,and halts the routines and behavior 883 when it loses control. Thebehavior also checks to see if the second or first start conditions havechanged, and if they change from positive to negative, then the routinesand behavior halt 883.

The above description of ballistic, semi-ballistic and persistentbehaviors is exemplary. The present invention contemplates implementingother versions of the behaviors. For example, steps 879 through 887 ofFIG. 18 may be substituted into the ballistic and semi-ballisticroutines for steps 848 and/or 822.

Tutorial Routines

In an embodiment of the invention, the software included in the controlsystem also includes tutorial routines able to perform thecharacteristics of a training system. The tutorial routines couldinclude a storage bank for providing cells of storage to each missionfor which the operator indicates that training information should berecorded. The training information can more aptly be called macros inthat it records, according to a timeline, an environmental set ofvariables, a command set, and a set of system variables. Preferably, thecommand sets include both commands sent by the operator and commandsgenerated and sent by routines within the remote vehicle's controlsystem 1155. The command sets and variables are recorded as use routinesable to recreate the recorded action according to a proper timeline.When a recorded mission is replayed, the use routines included in themacro are executed, which causes the control system to displayinformation to the user as though it were sensing the recordedenvironmental and system sensor information, and further causes theremote vehicle to mobilize according to the recorded commands. Theresult is a replaying of the events of the mission. The routines can bestored and used later as a pre-defined action sequence, and they mayfurther be used to train operators on the proper use of the controlsystem and remote vehicle. When routines are used as a pre-definedaction sequence, the replay routines call additional use routines thatsuppress environmental and system variable information and execute onlythe stored commands.

Robot Structure

FIGS. 19A and 19B illustrate an embodiment of a remote vehicle of thepresent invention. A mobile robot 10 has a head 122 that includes adrive camera 127 mounted thereon to provide visual information regardingthe environment of the mobile robot 10, an electro-optic infrared(EO/IR) module 4165 which uses LIDAR to map the environment and detectpossible obstacles, main drive treads 110 for propelling and steeringthe mobile robot 10, and robot-mounted antennae 131 for communicatingwith an operator via the control system. The mobile robot 10 alsoincludes rotatably extensible, treaded flippers 115 that can be deployedto augment traction and to overcome obstacles, and a robotic gripper 150for grasping or manipulating objects in the mobile robot's environment.The mobile robot 10 further includes an attack camera 151 to aid innavigation of the mobile robot and the robotic gripper 150.

FIG. 20 illustrates a mobile robot with both its robotic gripper 113 andattached upper arm 112 and lower arm 111 extended. Further shown is theextension of an arm 118 connected to the head 117, and the extension ofthe head 117 from the arm 118. Also shown is the advantage of having anattack camera 114 attached to the gripper's upper arm 112. The attackcamera 114 is able to display the gripper's position within itsenvironment in relation to the position of the gripper's upper arm 112.Using this information, the user can adjust the upper arm 112 toreposition the gripper 113 in its environment. Further shown is anextended flipper 116 which shifts the mobile robot's center of gravity.

FIG. 21 is a block diagram depicting an embodiment of a mobile robotcontrol system. Included in the control system 1155 is a single boardcomputer (SBC) 1110 such as, for example, a Freescale MPC5200. Amicroprocessor can be used in lieu of the single board computer 1110.Connected to the single board computer 1110 is a global positioningsystem (GPS) module 1135, a radio module 1150, and a wireless Ethernettransmitter and receiver 1140. A radio module 1150 is connected to thesingle board computer 1110 via an Ethernet switch 1190, and is furtherconnected to a radio antenna 1145. The user can control the controlsystem 1155 using a radio communicating over a secure connection createdby the radio module 1150 and the radio antenna 1145.

Further included in the control system 1155 in the illustratedembodiment is a power supply 1115 and memory 1125 including anycombination of ROM, volatile, and non-volatile memory. Also connected tothe single board computer are network 1 transmitter and receivers 1120,1121, 1122 and a network 2 switch 1130. The network 1 transmitter andreceivers 1120, 1121, 1122 provide communication between the controlsystem 1155 and an actuator assembly 1165 via a first connection wire1187 installed between the first network 1 transmitter and receiver 1122and second neck 1191 and a second connection wire 1186 installed betweenthe second network 1 transmitter and receiver 1120 and first neck 1194.The network 1 transmitter and receivers 1120, 1121, 1122 also providecommunication between the control system 1155 and the chassis 1160 via athird connection wire 1181 installed between the third network 1transmitter and receiver 1121 and the chassis 1160. The network 2 switch1130, on the other hand, provides communication between the network 2switch 1130 and each of the chassis 1160, the first neck 1194, and thesecond neck 1191 via a first connection link 1180, a second connectionlink 1188, and a third connection link 1180, between the chassis 1160,first neck 1194, and second neck 1191, and the network 2 switch 1130.

In an embodiment of the invention, the network 1 transmitter andreceivers 1120, 1121, 1122 include an RS485 transmitter for transmittingdata over an RS485 network using a point-to-point configuration betweeneach N1 (network 1) transmitter and receiver and a corresponding N1transmitter and receiver. For example, the communication between thecontrol system 1115 and the head 1195 is achieved by establishing acommunication link between an N1 a transmitter and receiver 1122connected to the control system 1115 and an N1 transmitter and receiver4315 connected to the neck's field programmable gate array (FPGA) 4330.A connection is then made between the N1 transmitter and receiver 4360connected to the neck's FPGA 4330, and the N1 transmitter and receiver4120 connected to the head's FPGA 4125. Thus, a network is createdbetween the SBC 1110 and the head's FPGA 4125 via the nodes created bythe N1 transmitter and receivers included in the control system 1155,the first neck 1194, and the head 1195. In an embodiment of theinvention, the network has a two-wire configuration providing halfduplex communication.

On the other hand, the network 2 (N2) transmitter and receiver 1130 ofthe illustrated embodiment includes an Ethernet switch for receiving androuting data over an Ethernet network. An example of this includescommunication between the SBC 1110 and the head 1195, created by the N2switch 1130 being connected to the SBC 1110 to establish a connectionwith the N2 switch 4320 connected to the neck's FPGA 4330 via acommunication link 1188. A connection is then made between the N2 switch4320 connected to the neck's FPGA 4330 and the N2 switch 4130 connectedto the head's FPGA 4125. The connections made create a network betweenthe SBC 1110 and the head's FPGA 4125. In an embodiment of theinvention, the network is a full duplex communication implemented viaEthernet cable.

Connected to the control system 1155 is a chassis assembly 1160 as wellas an actuator assembly 1165. In an embodiment of the invention, theactuators included in the actuator assembly 1165 are a first neck 1194connected to a head module 1195, and a second neck 1191 connected to athird neck 1192 which is further connected to a gripper module 1193.Also preferred is that each of the necks 1194, 1191, 1192, include asubstantially similar hardware circuit and software routine architecture4301. In an embodiment of the invention, both of the actuator moduleswithin the actuator assembly 1165 are connected to the control system1155 via connection wires 1187, 1186, and connection links 1189, 1188.The chassis 1160 is connected to the control system 1155 via aconnection wire 1181, and a connection link 1180. The present inventioncontemplates allowing the control system 1155 to communicate with theactuator assembly 1165 and the chassis 1160 via connection links only,wherein connection links include Ethernet, wire, wireless, radio, or anyother link that provides communication between circuits. The presentinvention also contemplates allowing the control system 1155 tocommunicate with the actuator assembly 1165 and the chassis 1160 viaconnection wires only.

An embodiment of a chassis assembly 1160 is further described in theblock diagram shown in FIG. 22. Included within the chassis 4001 basecircuit 4055 is an FPGA 4035 connected to a network 1 transmitter andreceiver 4050, and a network 2 switch 4045. In an embodiment of theinvention, the FPGA 4035 is a Xilinx XC3S1000. Further included withinthe base circuit 4055 are power regulators 4015 including circuitsconfigured to manage power within the chassis 4001. Additionally,included in the base circuit 4055 for motion control are motor drivers4030, motor encoders 4025, and a motor battery charger 4020. The chassis4001 also includes a number of motion control components connected tothe base circuit 4055, including incremental encoders 4060, drive motors4065, a brake 4070, thermistors 4075, and hall sensors 4080.

A block diagram of an embodiment of a neck module 4301 is shown in FIG.23. The neck module 4301 includes a base circuit 4305 having an FPGA4330 connected to a first network 1 transmitter and receiver 4315, asecond network 1 transmitter and receiver 4360, and a network 2 switch4320. Included within the base circuit 4305 are power regulators 4340that are circuits configured to regulate power within the neck module.The first and second network 1 transmitter and receivers 4315, 4360 areconnected to a payload connector 4310, 4355. The payload connectors4310, 4355 are plugs configured to mate with a corresponding plug on apayload such as an additional neck module 1191, 1192, a head module1195, or a gripper module 1193. Further included within the base circuit4305, to aid in motion control, are a clavical encoder 4345, a tilt 1encoder 4350, half-bridge drivers 4365, and h-bridge drivers 4370.Additional motion control components included within the neck module4301 and connected to the base circuit 4305 are brushless motors 4385,hall sensors 4380, and a thermistor 4375.

The neck module 4301 is also connected to a pan module 4390 and a tiltmodule 4395. The pan module 4390 allows the user to pan the distalportion of the neck about the neck's pivot point, while the tilt module4395 allows the user to tilt the distal portion of the neck about theneck's pivot point. A slip ring and magnet assembly for the connectionsbetween the pan module 4390 and the neck module 4301, between the panmodule 4390 and the tilt module 4395, and between the tilt module 4395and a further connection.

A block diagram of an embodiment of a head module 4100 is shown in FIG.24, and includes a base circuit 4105 with a centrally located FPGA 4125.Connected to the FPGA 4125 are a network 2 switch 4130, and a network 1transmitter and receiver 4120 which is further connected to a payloadconnector 4190. In an embodiment of the invention, the payload connector4190 is a plug configured to mate with a corresponding plug on a neckmodule 4301 such as neck module 1 1194. Additionally, included in thebase circuit 4105 are power regulators 4110 that are circuits configuredto manage power within the head module 4100. The base circuit 4105 isconnected to a set of video decoders 4150 via a CCIR-656 videocommunication bus 4145 and a serial bus 4140. Input to the videodecoders 4150 includes: (1) the output from a drive camera 4160; (2) theoutput from a differential NTSC receiver 4155 which is further connectedto the head module connector 4156; and (3) the output from theelectro-optic infrared (EOIR) module 4165. Output from the EOIR module4165 includes a near infrared (NIR) 4170 camera, a long wave infrared(LWIR) 4175 camera, and a laser range finder 4180.

An embodiment of a gripper module 1193 is shown in the block diagram ofFIG. 25. Located within the base circuit 4210 of the gripper module 4201is a FPGA 4240 connected to a network 2 switch 4245, and network 1transmitter and receiver 4235 that is further connected to a payloadconnector 4230. The payload connector 4230 is preferably a plugconfigured to mate with a corresponding plug on neck module 3 1192. Alsoincluded within the base circuit are power regulators 4220 includingcircuits for regulating power within the gripper module 4201, and thefollowing components for motion control: gripper encoders 4215;half-bridge drivers 4255; and h-bridge drivers 4260. Additional motioncontrol components connected to the base circuit 4210 and includedwithin the gripper module 4201 are brushless motors 4285, hall sensors4280, and a thermistor 4275. A video decoder 4265 is also connected tothe base circuit 4210. An attack camera 4270 located proximate to thegripper 4201 creates input to the video decoder 4265 so that the usercan view the gripper 4201 actions.

Network Configuration

FIG. 26 illustrates an embodiment of a network installed between thehead 4401 and the control system 4409 and the chassis 4406. There aretwo sub-networks included within the network: (1) the Ethernet networkcreated by the Ethernet switches 4427 included within each module andthe communication link 4415 that connects each Ethernet switch to acorresponding switch; and (2) the RS485 network created by the RS485transmitter and receivers 4430 and the connection wires 4412 thatconnect each RS485 transmitter and receiver to a correspondingtransmitter and receiver. An alternative network may include RS422transmitter and receivers in lieu of RS485 transmitter and receivers.Such an embodiment would provide full duplex communication, meaning eachtransmitter and receiver could simultaneously receive and transmit datapackets.

The RS485 network embodiment illustrated in FIG. 26 includes masternodes and slave nodes. A master node includes the node created by thesingle board computer 4436, the node created by the head 4401 and thenode created by the chassis 4406. Such nodes are master nodes becausethey provide a central point to which other nodes, slave nodes,communicate. An example of such communication includes the communicationbetween the single board computer 4436, the chassis 4406, and the head4401. The single board computer can receive information from the head4401 representative of a drive command and pass such information ontothe chassis 4406. This configuration would consider the single boardcomputer 4436 a master node, and the chassis 4406 and the head 4401slave nodes.

The network includes a control system 4409 with a single board computer4436 for processing information transmitted to the computer 4436 by eachnetwork. To gather such information, the single board computer 4436 isconnected to a single Ethernet switch 4427 which in turn is linked to anEthernet switch 4427 within the neck 4403 via a communication link 4415and an Ethernet switch 4427 within the chassis 4406 via a communicationlink 4415. The single board computer 4436 connects to two RS485transmitter and receivers 4430, one transmitter and receiver 4430 isconnected to a RS485 transmitter and receiver 4430 in the neck 4403 viaa connection wire 4412, and a second transmitter and receiver 4430 isconnected to a RS485 transmitter and receiver 4430 in the chassis 4406via a connection wire 4412. While an embodiment of the inventionincludes both an Ethernet network and a RS485 network, an alternativeembodiment can include only an Ethernet network. Such a network wouldprovide a full duplex communication network requiring lessinfrastructure than a RS485 network. The inclusion of both an RS485network and an Ethernet network is advantageous because it provides twonetworks, including an Ethernet network capable of communicating fromone far node to another, thus bypassing the token ring configuration ofthe RS485 network which requires passage of data through intermediatenodes.

Each actuator assembly includes a core circuit capable of implementingan alternative network that includes only an Ethernet network. The corecircuit includes a field programmable gate array 4418 with a mediaaccess controller 4433, where the FPGA is capable of managing multipledigital input 4421 and is further programmed to interface with the mediaaccess controller (MAC), which includes information or commandsgenerated either by the FPGA or the digital I/O 4421 to generate framesof data to be sent to other modules within the robot via packets sent bythe Ethernet switch 4427. Furthermore, the MAC is able to parse framesof data included within packets it receives from the Ethernet switch andextract information or commands that are either processed by routinesincluded within the FPGA or relayed to the digital I/O 4421. Due to thefull duplex communication network created by the Ethernet switch 4427,the MAC is able to simultaneously transmit and receive packets of data.The RS485 transmitter and receiver 4430, on the other hand, is halfduplex communication meaning that the transmitter and receiver 4430cannot transmit data and receive data simultaneously. “Actuatorassembly” refers to the head 4401, the neck 4403 or the chassis 4406.“Module” refers to a component within the head 4401, the neck 4403, thecontrol system 4409, or the chassis 4406.

Each Ethernet switch 4427 is also connected to a payload 4424, whereinpayload can include a drive assembly, an EO/IR, or other assembly. Useof an Ethernet switch 4427 allows for simultaneous communication betweenthe payload 4424 and other modules within the network including the head4401, neck 4403, and chassis 4406. An example of this would includevideo information transmitted from a payload 4424 such as the videodecoders 4150. The form of such information is a constant stream ofvideo feedback from the drive camera 4160. The example network createdusing the Ethernet switch 4427 allows for simultaneous receiving ofvideo information from the drive camera 4160 and transmitting andreceiving of information from the single board computer 4436.

FIG. 27 illustrates an embodiment of an Ethernet endpoint block 4439including an FPGA 4418 configured to include a MAC and connected to anEthernet switch 4427. The Ethernet switch 4427 is connected to the MACincluded on the FPGA 4418 via a medium independent interface bus thatprovides a logical interface with a communication protocol selecting theline speed and whether the connection is in a half or full duplex mode.The MAC parses the I/O ports 4445 included on the FPGA and generatesframes of data to be included in packets. The packets are transmittedout through the Ethernet switch 4427 to the rest of the modules in thenetwork. Included on the Ethernet switch 4427 are physical devices orline interfaces that handle the transfer of data from the Ethernet cableto the Ethernet switch 4427. An oscillator 4442 is included tofacilitate the exchange of information between the MII buses.

FIG. 28 illustrates an embodiment of the invention using the Ethernetendpoint block in the chassis, neck, head and EO/IR payload. Furthershown is the connection of various payloads to the Ethernet endpointblock as well as the running of Ethernet to other modules. Advantages ofan Ethernet endpoint block include: low EMC footprint, noise/bouncetolerant, modularity, can uniformly read/control each endpoint. Inaddition, an Ethernet network can handle far node-to-far nodecommunication.

Referring to FIG. 26, both the RS485 network and the Ethernet networkcan be used for communication. As an example, the Ethernet network canbe used for quick data transmission of video output from the EO/IRmodule to the single board computer 4436, while the RS485 network isused to transmit drive commands from the computer 4436 to the head 4401via the neck. Such a transmission would include the creation of videooutput by the EO/IR module 4424, the video output would then be relayedto the Ethernet switch 4427 where it would be transmitted directly tothe single board computer 4436 in the central control system 4409. Thevideo data would be transmitted via a cable 4415 connected at one end tothe Ethernet switch 4427 and at the other end to an Ethernet switch inthe neck 4403, and via a cable 4415 connected at one end to the Ethernetswitch 4427 in the neck 4403 and at the other end to an Ethernet switch4427 in the control system 4409. The Ethernet switch 4427 in the controlsystem 4409 is connected to the single board computer 4436 included inthe central control system 4409. Although the video information mustpass through two additional Ethernet switches, such information can passthrough each switch without the need for additional signal processing bythe intermediary Ethernet switches.

If the RS485 network is used to send a drive command from the singleboard computer 4436 to the head 4401, the data must first be sent to anRS 485 transmitter and receiver included in the control system 4409,which then transmits the data over a wire 4412 connected at the otherend to an RS485 transmitter and receiver located in the neck 4421. Thedata must then be processed by the FPGA 4418 included in the neck 4403and then passed on to a second RS485 transmitter and receiver 4430included in the neck 4403. The second RS485 transmitter and receiver4430 then transmits the data over a wire 4412 to an RS485 transmitterand receiver 4430 included in the head 4401 which is further connectedto an FPGA 4418 included in the head 4401. The RS485 network processesthe data at the intermediary node (in the neck 4403) between the head4401 and the control system 4409. The Ethernet network, on the otherhand, is able to send the data through the neck 4403, or intermediarynode, without requiring additional signal processing. Including both andRS485 and Ethernet network can prevent bottlenecks created by thepassage of large amounts of data over a single network, and furtherallows for faster transmission time due to the inclusion of multiplenetworks. Alternative embodiments of the system can include one or moreEthernet networks, or one or more RS485 networks. Further embodimentsinclude a full duplex RS485 network implemented using RS422 transceiversand receivers.

Gripper Manipulator

FIGS. 29A and 29B illustrate an embodiment of robotic arm 900 forfunctioning as a gripper affixed to the mobile robot 10. The robotic arm900 preferably includes a base 925 with circuitry required to controlthe arm. Additionally, the arm 900 includes a pair of actuators 920installed toward the end of the arm and able to grip and manipulateobjects. Further included near the actuators 920 are joints 915, 910which may be mobilized to alter the position of the actuators 920 inspace, and a camera 905 installed proximate the actuators 920 so thatthe operator may control actuator 920 movement based on video feedback.The actuators are connected to a secondary arm 930 which pivots at ajoint 901, and which is connected to a main arm that pivots at a joint940.

The joint 940 connected to the arm base 925 and the primary arm 935 canbe controlled by the operator via the control system outlined above.When drive commands are sent to the mobile robot 10 indicating that thejoint 940 should be actuated, a drive command is sent to the driveassembly located proximate the joint 940 which in turn causes a motorlocated in the drive assembly to mobilize actuators connected to thejoint 940 via gears and subsequently mobilize the primary arm 935.Similarly, drive commands sent to the drive assembly located proximatethe joint 901 connecting the primary arm 935 to the secondary arm 930can cause a motor located in the drive assembly to mobilize actuatorsconnected to the joint 901 via gears and subsequently mobilize thesecondary arm 930. Joints 915, 910, capable of mobilizing themanipulators 920 located on the gripper, can also be actuated via drivecommands sent to a drive assembly proximate the joint 915 and includinga motor. Additionally, the camera 905 installed near the gripperactuators 920 can input video data regarding the gripper's environmentand further transmit such data to the control system 1155 where it isfurther transmitted to the control system to be displayed on a screen sothat the operator may view the gripper's environment.

Software Architecture Behavior System Overview

In accordance with the present invention, a remote vehicle (such as themobile robot 10 described above) has included within its control system1155 a behavior system comprising software routines and circuits. FIG.30 illustrates an embodiment of a behavior system to be included withina remote vehicle. At the heart of the system are behaviors 715 includingdifferent behavior software routines that further include behaviorsoftware subroutines. The behavior software routines are the mainroutines and are referred to as the individual behaviors, for examplethe stair climbing behavior software routine is referred to as the stairclimbing behavior. The individual behaviors 715 include within themsub-routines, which are routines that implement the actions associatedwith each behavior. An example would include the stair climbing behaviorwhich includes within it a stair climbing routine, a maintain alignmentroutine, as well as other routines necessary to fully implement thestair climbing behavior.

In an embodiment of the invention, each behavior includes a status checkroutine that constantly checks sensor input to determine a change instart condition. When the start condition is a positive value, thebehavior initiates a routine, included within the behavior that beginssending software commands to an arbiter (coordinator) 710 includedwithin the behavior system. The commands sent to the arbiter 710 arevotes that tell the arbiter 710 that the behavior would like control ofthe actuators used by the routines included within the behavior. Anexample of this would include the stair climbing behavior, that respondsto a positive change in its start condition by sending votes to thearbiter 710 indicating that stair climbing would like control over thetilt sensor, the drive assembly, the drive and attack cameras, and allother actuators and manipulators needed to implement the stair climbingbehavior. Each behavior could have its own specific set of routines, orsome or all behaviors 715 may be able to share a common set of routinesincluded within the behavior system.

Also included within each behavior is a priority. FIG. 31 illustrates alisting of behaviors within the behavior system in an exemplary order ofpriority. As shown, a behavior such as the obstacle avoidance behavior7059 has a higher priority than the stair climbing behavior 7068 as itis more important that the remote vehicle avoid an obstacle than climb astair. This practicality can be displayed in a situation where there isa bomb located on a set of stairs, and the behavior system stops thestair climbing behavior 7068 on detection of an obstacle by a sensor, sothat the higher priority obstacle avoidance behavior 7059 may controlthe remote vehicle's drive assembly to drive away from the obstaclewhich in this case is a bomb. Were the obstacle avoidance behavior 7059is not a higher priority than the stair climbing behavior 7068, theremote vehicle would have continued to drive toward the bomb, likelyhitting it and causing injury to the remote vehicle and those humanspresent in the surrounding environment.

The arbiter 710 included within the system is a software routine thatmanages the votes and priorities of the individual behaviors 715 inconjunction with the scheduler 730, to determine when and in what orderthe behaviors 715 will gain control over the actuators and manipulatorswithin the remote vehicle. To accomplish this, the arbiter 710, at anypoint in time, reviews all the behaviors 715 currently voting forcontrol. To determine which behavior 715 will gain control, the arbiter710 reviews each voting behavior's priority level, and the scheduler's730 indication of which behavior should gain control based on the lengthof time that the current behavior or a past recorded behavior, has orhad control of the actuators and manipulators. An embodiment of theinvention includes a scheduler 730, but alternative embodiments mayinclude a system with a single arbiter 710 that determines thecontrolling behavior based on priority level and votes.

To input sensor output to the behaviors 715 and their correspondingroutines, the system has a set of virtual sensors 720 in communicativeconnection with a set of sensors 725. The sensors 725 can include sensorcomponents and related circuitry and software routines that providefeedback representative of the remote vehicle's current external andinternal environment. An example includes a wireless receiver providingfeedback regarding detectable wireless signals within the remotevehicle's external environment, and a brake that uses an electricalswitch to provide feedback about the state of the brake within theremote vehicle's internal environment via an electrical signal generatedwhen the electrical switch is closed. Output from the sensors 725 isfurther conditioned by virtual sensors 720 which include circuits andsoftware able to input sensor 725 signals and process the signals toprovide outputs representative of each signal, but in a form able to beprocessed by the routines within the behaviors 715.

In an embodiment of the invention, each of the sensors 725 has acorresponding virtual sensor 720 configured to the requirements of thatsensor. An example is the brake sensor which outputs an electricalsignal in response to the actuation of the brake. The virtual sensor 720associated with the brake sensor may be configured to input the rawanalog signal into a signal processing circuit that further conditionsthe analog input and outputs a digital signal which is further processedby a software routine that outputs a logic value representative of thebrake's status. Output from the virtual sensors 720 is inputted to thebehaviors 715 where it is used in behavior routines to mobilize theremote vehicle and further respond to raw sensor output.

Included within the behavior system are actuators 705 able to respondsto output from virtual actuators 701 by mobilizing and performingactions. To control the actuators 705 within the robot 10, the behaviors715 output control commands which can include drive commands,communication commands, and other commands able to control actuatorsincluded on the robot 10. Each actuator is able to receive drivecommands in a particular format. The virtual actuators 701 includesoftware routines and circuits able to input the software controlcommands from the behaviors 715, and convert them into control commandsable to be received by the actuators 705. In particular, the motorsincluded within the chassis can take drive commands in a format thatpreferably includes an electrical signal. The virtual actuator 701associated with the motors within the chassis are able to take thesoftware command generated by the behaviors 715 and convert the commandinto a signal that is then transmitted to the motors within the chassis.

Autonomous Remote Vehicle Behaviors

In an embodiment of the invention, these behaviors are included on theremote vehicle in memory, and are executed by the single board computer.There are three types of behaviors: Ballistic, Semi-Ballistic, andPersistent. The descriptions below refer to mobile robot 10 describedabove. The present invention contemplates employing autonomous behaviorson a variety of remote vehicle types as would be appreciated by one ofordinary skill in the art.

Ballistic Behaviors Stair Climbing

The stair climbing behavior drives the mobile robot 10 to traverse a setof stairs in an autonomous manner, after receiving a command to initiatethe behavior and information indicating the location of the stairs fromthe operator. The mobile robot 10 may include a pitch/roll sensor thatindicates whether the mobile robot 10 is tilted relative to the ground,which is used by the stair climbing behavior to decide whether themobile robot 10 should continue climbing the stairs.

The mobile robot 10 can be positioned in the vicinity of a staircase920, and the user may initiate the autonomous stair climbing behavior bysimply identifying the location of the stairs 920 and inputting acommand to activate the stair climbing behavior. The mobile robot 10 canthen ascend or descend the stairs 920 without requiring further inputfrom the operator.

Referring to a control system console illustrated FIG. 32, an embodimentof a stair climbing behavior is initiated when the operator navigatesthe mobile robot 10 to within a threshold distance of the stairs, suchthat the stairs are visible in the image data displayed both in a drivecamera window 261 and an attack camera window 262. The operatorpositions a first selector 267 to enclose or abut a region of the window261 corresponding to the stairs, and similarly positions a secondselector 268 to enclose or abut a region of the window 262 that alsocorresponds to the stairs.

With the target stairs 920 identified by the first and second selectors267, 268, the operator can then trigger the stair climbing behavior byclicking an on-screen button or otherwise inputting a command thatcauses transmission of a control signal that activates the stairclimbing behavior. In accordance with an embodiment of the invention,the operator further inputs whether the mobile robot 10 should climb upthe stairs or descend the stairs. In another embodiment, the mobilerobot 10 includes a routine for autonomously determining whether thetarget stairs 920 are ascending or descending relative to the mobilerobot 10, and informs the stair climbing behavior accordingly.

FIGS. 33A and 33B illustrate positions of the mobile robot 10 relativeto the target stairs 920 as the mobile robot ascends or descends thestairs 920 in accordance with the stair climbing behavior. The mobilerobot 10 may initially extend the flippers 115 to a predetermined angleto facilitate the stair climbing operation. FIG. 33A illustrates anembodiment of the invention wherein the flippers 115 may rotate out to a180° angle relative to the main treads 110 to ensure contact with thestairs 920 and to raise the front end of the mobile robot 10 up onto thestairs 920. When descending, the mobile robot 10 may instead extend theflippers to an angle 77 that is approximately 45° relative to the maintreads 110 (see the embodiment of FIG. 33B).

When the tilt sensor of the mobile robot 10 indicates that the angle oftilt of the mobile robot 10 is zero relative to the horizon, the stairclimbing behavior may stop and navigation authority may be resumed byanother routine.

FIG. 34 illustrates an embodiment of a method for performing the stairclimbing behavior. At step 2901, the behavior initializes internalvariables (by setting the initial turn rate and roll rate to zero, forexample), and then determines at step 2902 whether the mobile robot 10should ascend the stairs. If so, the mobile robot positions the flippers115 to the appropriate angle for ascending the stairs at step 2903,outputs a speed value for ascending the stairs at step 2904, andproceeds to traverse the stairs at step 2907. The mobile robot 10 mayascend the stairs at a predetermined speed while under control of thestair climbing behavior. The predetermined speed may be, for example 0.2meters per second.

If the mobile robot 10 is determined at step 2902 not to be intended toascend the stairs, then the behavior positions the flippers 115 to anangle appropriate for descending the stairs, sets a speed appropriatefor descending stairs, and proceeds to navigate the stairs at step 2907.Thereafter, the behavior may optionally perform steps to maintain themobile robot's alignment with the stairs at step 2908 (for example, toprevent the robot falling off the side of unprotected stairs), and thendetermines at step 2909 whether the tilt sensor indicates the existenceof tilt.

If tilt exists, the behavior continues to ascend the stairs 920autonomously by returning to step 2907. Otherwise, step 2910 stops themobile robot 10 from proceeding further, and returns the flippers 115from the ascending or descending position back to the neutral,undeployed position at step 2911.

To ascertain whether there are more stairs to traverse, the stairclimbing behavior may use a median pitch filter routine to integratetilt sensing information from multiple sources, and to reduce falsepositive determinations of being level. In one embodiment, the medianpitch filter routine tracks pitch information from the tilt sensor anduses only those values that fall within the median of all previouslyrecorded values. Accordingly, the routine can reduce the detrimentalimpact of transient values on the determination of whether the stairtraversal is complete.

According to an embodiment of the invention, the median pitch filterroutine stores native pitch/roll sensor output in memory. An on-boardtimer then increments and the routine periodically checks whether it hasbeen incremented by a full half second. If so, then the routine moves onto the next step. Otherwise, the routine stores the tilt sensor output,and increments the timer. The median pitch filter routine then examinesthe pitch/roll sensor native output over the full half second anddetermines the respective highest and lowest frequencies of the signal.Using this information, the median pitch filter routine then calculatesthe median frequency. The median pitch filter routine outputs thiscalculated median frequency as the pitch/roll sensor output to therobot's control assembly.

The maintain alignment routine may be used by the stair climbingbehavior to keep the mobile robot 10 moving in a consistent directionwith respect to the vertical axis of movement, and allows the mobilerobot 10 to ascend or descend stairs with a turn rate magnitude of zero.While moving forward with a zero turn rate, for example, the routinesimultaneously samples the roll angle as determined by the pitch/rollsensor output and subsequently calculates a turn rate magnitude from theoutput. In an embodiment of the invention, the equation by which theturn rate magnitude is calculated may be approximately k*X degrees persecond, in which k is a constant having a value within the range of 1/10to 3 and X represents the roll angle. Other embodiments may usediffering formulas. At one step, the routine checks the roll angle todetermine whether it has a value other than zero. If so, the routinereturns to the first step and moves forward with a roll angle of zero.Otherwise, the routine re-aligns the mobile robot 10 by turning themobile robot 10 by the calculated turn rate magnitude. Once the mobilerobot 10 is re-aligned, the process goes back to the first step andcontinues to climb forward with a roll angle of zero.

This embodiment of the stair climbing behavior utilizes a tilt sensorallowing the robot 10 to position itself without the need for walls.Alternative embodiments may include the use of a SICK LIDAR sensor todetect walls to position the robot as the robot moves up the stairs, orthe use of SONAR to detect walls and position the robot as it moves upthe stairs. Other alternative embodiments include a fully autonomousversion of stair climbing that is implemented upon the detection ofstairs. Such a version may include a sensor placed toward the outer rimof the robot's lower chassis to detect negative obstacles such asdownward stairs, or may require multiple sensors to indicate that thereis an obstacle within the allowed height, meaning that software routineswithin the robot would associate certain dimensions with stairs. Stillother alternative embodiments include a routine that commands the robotto re-position its arms to 180° when it reaches the top of the stairs,or a robot that utilizes a magnetic compass or IMU in addition to or inlieu of a tilt sensor.

Preset Action Sequence

FIG. 35 illustrates an embodiment of a preset action sequence behaviorby which an operator can create a custom action sequence routine that isan aggregation of user-chosen routines and behaviors. An action sequenceroutine may consist of a combination of available robot behaviorroutines and events. Alternatively, the operator can include actions andmovements available to the mobile robot 10 but not defined by apre-existing behavior or routine. An exemplary method for constructingthe preset action sequence behavior using a console as illustrated inFIG. 35 includes depressing soft keys 253 either by moving a mouse overthe button image on the screen 261 and then depressing a mouse button,or by contacting and applying a force to the area on the screen 261 thatcorresponds to the button image 253. Once the button is actuated acommand is sent to the control system 1155 to include the action orbehavior routine in the preset action sequence behavior. Further methodsof input include actuating buttons or switches of the control systemdescribed above, or by any other suitable method. Alternatively, asoftware routine of the preset action sequence behavior can be loadeddirectly into the mobile robot memory 1125, for example via an externalmemory device inserted into the mobile robot 10. Furthermore, the presetaction sequence behavior can be created by recording a macro of theactions of the robot while the user is driving the robot and actuatingvarious autonomous behaviors. Additionally, the present action sequencecan be created using any combination of the methods described above.

Once the preset action sequence behavior is initiated by the operator,the operator can then input the desired sequence of behaviors, actions,and events in step 3901. Such a sequence can be any combination ofautonomous behaviors, actions, and events available on the robot, andmanual behaviors, actions, and events available on the mobile robot 10.Upon entering step 3901, a routine included within the preset actionsequence behavior routine determines if the combination of behaviors,actions, and events chosen by the user is allowed in step 3902. Such adetermination is made by evaluating the requirements for each behavior,action, and event and then inputting the determined results against aseries of error checking routines that evaluate whether the selectedcombination is allowed per requirement vectors stored in memory. Shoulda combination not be allowed, the routine included in step 3902 willeither alert the user of the error and perhaps require them to chose analternative sequence, or exit the preset action sequence behaviorroutine step 3907.

An example of a combination action sequence that might be precludedwould be the use of Speed Boost in addition to the Stair Climbingbehavior. A Boolean value representative of whether the chosen actionsequence is allowed is outputted. Should the value not be allowed, thenthe behavior routine either re-displays the initial action entry screenand perhaps instructs the user to enter a different action sequence step3901, or exits the preset action sequence behavior. Alternatively, if aspeed value is selected in the Speed Boost behavior that is incompatiblewith the Stair Climbing behavior, then the behavior routine mayre-display the initial action entry screen and instruct the user toenter a different value for the speed. Other embodiments may makesubstitutions for the forbidden actions and proceed with the behavior'ssubsequent steps. In an embodiment of the invention, the screen alsorelays to the operator the conflicts present in the previous list ofchosen actions. Alternatively, the screen may request that the operatorchange only the actions that are not allowed.

Further referring to FIG. 35, upon identification of an allowed actionsequence, the behavior routine stores the selected sequence step 3903 inmemory 1125. Once an allowed sequence is stored, the control system 1155executes the preset action sequence starting in order from the firstaction chosen by the operator in step 3904. The step of initiating anaction step 3904 is followed by a check to see if operator input isneeded for the action to perform properly in step 3905. In an embodimentof the invention, a need for operator input is only indicated inabsolute cases so that efficiency and autonomy is preserved. In anembodiment of the invention, autonomy is enhanced by allowing the mobilerobot 10 to determine the value of operator input based on prioroperator data and environmental data. In other embodiments, the mobilerobot 10 may refrain from inputting data for operator inputs and shouldindicate when operator input is needed. If the mobile robot 10determines that operator input is needed, it should prompt the operatorto input the required data and then perform the action in step 3909.Example user input may include any one of a speed value, time durationof an autonomous behavior, a direction heading, or other value needed toexecute any one of the included behaviors, actions, or events. Shouldthe initiated action need no further user input, the behavior routinewill then continue to execute autonomously and perform the action instep 3909.

Once the action has been performed in step 3909, the mobile robot 10checks to see if there are further actions listed in the sequence step3906. In the event that additional actions remain, the next action inthe sequence is initiated and the operator input check is done beforethe action is performed. Otherwise, if no additional actions remain, themobile robot 10 exits the preset action sequence behavior in step 3907.An embodiment of the invention allows the mobile robot 10 to enteranother behavior or event when no additional actions remain.

An alternative routine may substitute the portion of the behaviorroutine associated with the execution of an action 3910, with a singlestep of executing the behavior routine as recorded. Such a step wouldnot allow the user to input additional data, but would rather executethe actions in the order in which they were chosen.

Click-to-Drive and Click-to-Grip

In an embodiment of the invention, the robot includes two “fire andforget” behaviors allowing an operator to chose a destination pixeldisplayed to the operator via the above-described control system andeither drive toward the destination or move toward the destination andgrip an item. Both of these behaviors are intended for one-time use andallow the operator to accomplish complex actuation and driving with lessintervention. The click-to-grip behavior also utilizes image data fromfirst and second cameras displayed in respective first and secondwindows 261, 262 to identify a target object for the behavior. Theembodiment of FIG. 36 illustrates that the robot's gripper can bemanipulated to move toward an object and grip the object in response toa user clicking on the object within an image of the environment. Toaccomplish gripping, the operator positions the first and secondselectors 267, 268 to identify the target object 3010 in both the drivecamera display 261 and the attack camera display 262. In an embodimentof the invention, the operator has already actuated a button or switchto actuate the click-to-grip behavior. Alternatively, the operator mayadditionally actuate a “begin behavior” button or switch, whichtransmits a control signal to the mobile robot 10 that activates theclick-to-grip behavior.

Once the object is chosen in both displays 261, 262, the position of theobject within those displays is used to calculate its coordinates. FIG.37 illustrates an embodiment of a click-to-grip routine executed duringthe click-to-grip behavior. Upon selection of the object by theoperator, the routine stores the image coordinates from the attackcamera video display 8103 and the drive camera video display 8106. Usingthese image coordinates and stored values corresponding to theresolution of the attack camera and the drive camera, the routinecalculates the destination point 8109. The coordinates are projectedinto the robot's current environment 8112 and from the projectedcoordinates, a set of rays are calculated 8115 that are representativeof travel vectors from the robot's current position to the destinationposition. The rays are then corrected 8118 and a check is done to ensurethat the gripper is on the correct side of the turret 8121. If thegripper is not on the correct side of the turret, the robot moves thegripper 8124. Once the gripper is correctly positioned, a check is doneto ensure that the drive camera is synched up with the object to begripped 8130. If the camera is not synched up, then the robot can movethe camera 8127 which may include moving the camera to a positionincluded within the newly calculated travel vector. Once the drivecamera is synched up with the destination object, the robot moves thegripper toward the destination point 8133 grips the object 8136 afterarriving at the destination point.

Similarly, click-to-drive uses video feed from the attack and drivecameras to determine a destination point. FIG. 38 illustrates anembodiment of a routine included on the robot for implementingclick-to-drive. The routine responds to activation of the click-to-drivebehavior and selection of a destination pixel by storing the selectedcoordinates from the attack and drive camera video displays 8153. Oncethe coordinates are stored, the routine calculates a destination point8156 and projects the destination point onto the robot's current groundplane 8159 so that directional rays can be calculated 8162. Oncecalculated, the rays are corrected 8165 and used by the robot to drivetoward the destination point 8168. Like click-to-grip, click-to-drive isa fire-and-forget behavior and therefore will terminate once the robotreaches the destination point. In an embodiment of the invention, theclick-to-drive and click-to-grip behavior include fail safe routineswhere the behavior will terminate and reset when the robot is powereddown, loses communication with the control system, or is interrupted bya behavior with a higher priority.

The present invention also contemplates an embodiment where theclick-to-grip and/or the click-to-drive behavior are operable in twomodes: (1) a high degree of precision mode and (2) a low degree ofprecision mode. The high degree of precision mode allows the operator tochoose the object's corresponding pixel image on the display screen andresponds to the actuation of a button triggering a gripping sequencethat takes the precise pixel location and converts it to a destinationpoint. The low degree of precision mode, on the other hand, allows theoperator to choose a heading direction and responds to actuation ofbutton triggering a sequence that flies the gripper in the generaldirection of the objects included within the heading. An embodiment ofthe invention includes a robot with the ability to choose a path withinan approved heading that provides the most direct route and avoidsobstacles. In both modes, the gripper moves using a “fly in motion,”which actuates all joints in a fluid motion. Fly-in motion moves theclaw forward in a single fluid motion actuating all necessary joints tokeep the direction of movement uniform. The gripper will stop if itencounters unexpected obstacles, and will move forward 50% of theestimated distance to reduce the risk of over-travel. An alternativeembodiment of the invention moves forward 100% of the estimateddistance. After moving 50% of the estimated distance, the operator mayreposition the gripper and then trigger the click-to-grip behavioragain. Both modes can also move away from the object using the same paththat was used to move the gripper forward. Further alternatives includea robot that:

uses sensors to identify the basic shape of the object and orient thewrist joint of the manipulator arm accordingly;

has motors that can fine tune the manipulator arm;

has a pre-programmed manipulator arm motion routine;

uses analysis of the object's dimensions to close the gripper's fingersuntil the aperture is the required size or until torque sensors in thegripper indicate that the fingers have a required amount of resistance;

has a gripper that grips the object until the grip routine exits;

has an emergency halt routine that halts the gripper and awaitsinstructions if an unexpected obstruction is encountered;

uses camera triangulation, camera depth-of-field, and object sizeestimation to estimate the range to the target; and/or

has a distance sensor to provide distance feedback used by the routineto adjust movement toward the object to be gripped.

Custom (Preconfigured) Poses

As shown in FIGS. 39 and 40, once a preconfigured pose available via aGUI, soft button, dedicated button, switch, toggle, or other selectiondevice has been selected, the robot must move some or all of theflippers, neck, and head with respect to the robot main body and maindrive in order to move from the present pose to the preconfigured pose(e.g., prairie dog P16, stowed P10, driving on a flat surface P14,driving on a bumpy or angled surface P20, stair climbing). Some robotconfigurations may use symmetric flipper arm and body (each the samesize), providing alternative poses (e.g., inverted Y in which the bodyand/or head is positioned directly above a steepled symmetric flipperand body, inverted arrow in which body and/or head are positioned aboveV-oriented symmetric flipper and body—which may further require invertedpendulum gyroscopic AKA “Segway” balancing). Only a few exemplary posesare shown in FIGS. 39 and 40. Actions by the robot or in which “therobot moves” mean that the actuators of the robot are driven under motorcontrol and amplification as directed by the controller circuit on therobot itself.

Changing or returning to a preconfigured pose from any arbitrary posemay require determining the current position and orientation of therobot's body, drive or flipper arms, neck, and/or head. In an embodimentof the invention, the robot's movement is determined through the use ofmotor encoders (relative or absolute) and the robot's camera (withcamera lens) is mounted at a controllable height above the robot's body,as controlled by the movement of the neck. A pan/tilt head with a camerais mounted at the top of the neck. The neck may contain a physical neckindex switch allowing the system to reset the neck location in anabsolute sense as the neck's movement passes through a specifiedlocation. By using the starting angle of the neck and motor encoders,the angular location of the neck at any given time can be calculated.Likewise, the pan and tilt position of the head camera can be calculatedusing the start locations. Alternatively, some or any of the flipper armangle, neck angle, head angle (tilt), and head turn (pan) may useabsolute encoders.

By using the current locations of each of the robot elements (body,flipper arm, neck, head pan & tilt) via motor encoders or otherproprioceptive sensing, the static geometry of the robot itself (forexample, the length of the neck and its arc of travel, the distance fromthe center of rotation to the base of the neck, known x, y, z locationsof the center of mass of each of the body, flipper arms, neck, head) andon-board orientation sensors in any robot element (accelerometers, tiltsensors, gyroscopes, and/or horizon detection), it is possible toproduce a frame of reference for each robot element. Each frame ofreference is represented by a matrix giving the x, y, z location of therobot element and the rotation vectors for forward, left and up.

A similar frame of reference can alternatively be created for eachelement in turn using well-known Denavit-Hartenberg Parametercomputations, e.g., going from the robot base toward the head and cameralocation. For example, the frame of reference for the neck can becomputed using the body frame of reference, Denavit-HartenbergParameters describing the neck geometry, and the current neck angle ofrotation. Using these three inputs, a new frame of reference can becomputed for the neck. Similarly, the pan frame of reference iscalculated, followed by the tilt frame of reference. In an embodimentwhere the camera is attached to the head, the frame of reference for thehead is the frame of reference for the camera itself.

Such calculations from sensor data, performed on the robot itself,permit the robot's starting state to be determined, e.g., including therobot's location and vector (frame of reference) and the camera'slocation and vector (frame of reference). Embodiments of the inventionmay not require all of the calculations. For a particularly robustrobot, merely the element configurations as expressed by the relativeposition of the body, flipper arms, neck, and head may be sufficient.

FIG. 39 illustrates an embodiment of a technique for moving betweenpositions—by mapping necessary states between preconfigured poses andcurrent states, including necessary states P24. This state diagram showsthat for some robot configurations, a loop among the states is notnecessarily formed, and the path between intervening states may belimited to passing through particular sequences of intervening states.For example, a robot in stowed pose P10 (solid lines indicating apreconfigured pose), with head and neck retracted and flippers alignedalong the main tracks, may be placed in any of three exemplarypreconfigured poses (prairie dog P16, bumpy travel P20, and flat travelP14).

In order to move to prairie dog pose P16, in which the robot is stablyelevated on the flipper tracks with the neck elevated to a substantiallymaximum height, the robot must begin by lifting the body, by turning theflipper tracks counterclockwise F-CCW (from the side shown in FIG. 39).As the robot moves through intervening poses P12, the center ofmass/gravity of each of the body, neck, and head are maintained abovethe midpoint of the flipper arms. As shown in FIG. 39, this may beaccomplished by specifying predetermined intervening states andactuations for the robot to pass through (e.g., where “CW” is clockwisefrom the side shown in FIG. 39 and “CCW” is counter clockwise, firstarranging the body and head above the arms by moving the body only viathe flippers F-CCW, then by elevating the neck N-CCW and head H-CW, thenby unfolding all at once vertically flipper F-CCW, neck N-CCW, and headH-CW).

To return to the stowed position P10, or as shown in FIG. 39 to move toeither of the driving positions P20 or P14, the robot moves back throughthe necessary states in the opposite order and with the opposite CW orCCW motions.

In order to move to, e.g., bumpy driving pose P20, in which the robot isstably positioned to be driven at slower speeds on the main tracks withthe flipper tracks up to handle small obstacles, the neck and head beingpositioned behind the main body to provide a driving view but maximumstatic stability, the robot must begin by turning the flipper tracksclockwise F-CW (from the side shown in FIG. 39). As the robot movesthrough intervening poses P22, the flipper arms move to aready-for-driving (or potentially climbing) position. As shown in FIG.39, this may be by specifying predetermined intervening states andactuations for the robot to pass through (e.g., first arranging theflipper by moving only the flippers F-CW, then by elevating the neckN-CCW and head H-CW).

In order to move to, e.g., flat driving pose P14, in which the robot isstably positioned to be driven at higher speeds on the main tracks withthe flipper tracks also in contact with the ground, the neck and headbeing positioned behind the main body to provide a driving view butmaximum moment about the leading end to resist flipping forward uponsudden stops or braking, the robot continues from the bumpy driving poseP20 by moving the flippers F-CW, elevating the neck N-CCW and tiltingthe head H-CW (from the side shown in FIG. 39). In order to “return” toany of the previous preconfigured poses, the robot must pass through theintervening preconfigured poses and intermediate poses.

As discussed, FIG. 39 demonstrates a model in which intervening andintermediate poses are predefined states on a closed, not necessarilylooping, state map, in order to ensure that the robot does not tip over,self collide, or inappropriately lose balance or pose in transitioningfrom a present pose to a preconfigured pose. This is a methodical, butless flexible approach than having the robot actively maintain balanceusing proprioception, tilt, acceleration, and rotation (gyro) sensors.

FIG. 40 shows an embodiment in which the robot, although passing throughsimilar states, constantly monitors balancing proprioception (positionencoders), tilt, acceleration, and/or rotation (gyro) sensors. Thissystem may deal more successfully with uneven ground (shown in FIG. 40)than a system using predefined positions. As shown in FIG. 40, a roboton level, tilted, or uneven ground in the stowed position P30 may bemoved into, e.g., prairie dog pose (on uneven ground P32), flat drivingpose (on uneven ground P34), and bumpy driving pose P36 by monitoringposition encoding, calculating the overall center of gravity of therobot over that portion of the robot in contact with the ground (eitherthe main body, the main body and flipper tracks, or just the flippertracks), maintaining the individual centers of gravity of the body,flipper arms, neck, and head in positions over a stable center of groundcontact, and monitoring and/or controlling acceleration and movement ofthe elements to obtain relative tilt, orientation to terrestrialgravity, and/or static and/or dynamic stability. As shown in FIG. 40,because the preconfigured poses are reached by active monitoring andcontrol of balance, the robot need not pass through all preconfiguredintermediate pose states, but will pass through arbitrary, yet stableand balanced poses P40, on its way from one pose to another (e.g., frombumpy driving P36 to prairie dog P32 without passing through the stowedconfiguration P30). As such, the state map P38 will permit directtransition from one preconfigured pose state to another through acontinuously changing, but continuously balanced pose transition, andfrom arbitrary current poses P42 directly to preconfigured poses P30 viaa continuously changing, but continuously balanced pose transition (or asuccession of continuously balanced pose transitions). The robot mayalso seek preconfigured poses by moving only from a present positioninto a confined solution space of next positions that includes onlybalanced poses.

In an embodiment of the invention, the robot may display to the user arepresentation of itself within its environment (see FIGS. 11 and 12)based on current information from the robot to the control system. Uponthe user selecting a pose, the robot flippers and body move to anglethemselves using accelerometers that input a direction of gravityreference. To achieve, for example, a prairie do position, accelerometerinput is used by the robot to position its body at about 55° plus orminus about 2° from the horizontal (with respect to gravity). The robottries to position its body at this orientation even on non-level ground.The robot is kept balanced during pose transitions by monitoring itsbody position relative to the horizontal. As can be seen from theillustrated prairie dog position, the neck may be set at about 130°relative to the body.

In an embodiment of the invention, the prairie dog pose may need to bedeactivated to tilt the robot head, but no to pan it.

In an embodiment of the invention, the robot returns from the prairiedog pose to a driving position quickly, if not gracefully, to facilitateexpedient withdrawal or other movement.

In an embodiment of the invention, the robot can be controlled toactively return to a preconfigured pose set when disturbed via thecontinuously balanced pose transition, including a self-righting routineintervening before the robot seeks the last set preconfigured pose. Forexample, if the robot is temporarily forced into a different pose, or istipped over or otherwise disturbed, using tilt sensors, proprioceptiveencoders, accelerometers, and/or gyro sensors, it may detect this andinitiate seeking of the predetermined pose. In moving to ad frompreselected poses, a embodiment of the invention further includes aninherent collision avoidance behavior or system that uses a geometricmodel of the robot in its environment to ensure that the robot partswill not collide with each other when moving to and among poses.

Autonomous Flipper Behavior

Autonomous flipper behavior allows an operator to operate the robotmanually while the flippers are in an autonomous mode. The behaviorautonomously identifies surface conditions and can use this data totrigger the autonomous flipper behaviors. When constantly running in thebackground, autonomous flipper behavior is considered a persistentbehavior. Possible terrains to identify include: (1) soft terrains whichmay include snow and sand; (2) hard smooth terrains such as buildinginteriors or roadways; and (3) firm broken terrain such as fields ordirt roads. For each terrain, there is a corresponding flipper positionthat works best. For example, flippers rotated into the retractedposition work best on soft terrains, and flippers extended upwards worksbest on hard smooth terrains. Other inputs that could trigger autonomousflipper behavior include the robot being lifted high off the ground byan object which the robot traversed. In an embodiment of the invention,autonomous flipper behavior draws upon data flows alreadypresent—operator drive commands, accelerometer spectral density, andload on the drive motors. More experienced users may disable theautomated behaviors and manually control the flippers as needed.

An embodiment of the invention determines terrain type using spectraldensity of the vehicle's onboard accelerometer readings to identify theamount and type of vibration the robot is encountering. This data iscorrelated with other inputs to identify conditions requiring flipperposition modification. For example, high centering shows negligibleaccelerometer vibration and rough terrain shows large jolts. Alternativeor addition sensor input to consider includes video jitter and flow,comparing odometry to an external reference such as GPS, and trackingthe fiber optic control line's feed-out speed. High centering asituation where the treads do not make solid contact, resulting from anencounter with an obstacle high enough to lift the robot's chassis. Theideal configuration for driving over unknown terrain for instance iswith the flippers in front and raised at 30 to 45 degrees relative tothe surface.

In an embodiment of the invention, operation in soft terrain causes theautonomous flipper behavior to maximize the amount of driven surfacecontacting the ground. To accomplish this, the flippers are lowered infront of the vehicle or tucked along the side of the vehicle. When theflippers are extended, there is a possibility that a flipper will diginto the soft ground.

In high center events, an embodiment of the invention directs thevehicle to mobilize the tracks in a swimming motion, continuouslyrotating the flippers overhand and driving the tracks only when theflipper is in contact with the surface. When engaged, tracks arepropelled at the same rate that the flipper is expected to pull thevehicle forward. In swimming, the optimal speed of flipper rotation isbased not on the absolute length of the flippers but on their effectivelength (the area in effective contact with the ground), which changes asthe surface density changes. By measuring the changes in angle of thevehicle as the flippers rotate, it is possible to calculate optimalspeeds.

Retro Traverse

In an embodiment of the invention, a retro traverse behaviorautonomously navigates the mobile robot 10 back along a return pathinterconnecting various previously traversed coordinates. The retrotraverse behavior may be activated by user request or automatically whentrigger conditions are detected by the mobile robot 10, such as when nocontrol signal has been received after a threshold period of time; ormay be activated explicitly by the operator inputting an activationcommand. If automatically triggered, retro traverse acts as a persistentbehavior.

To perform retro traverse according to an embodiment of the invention,the mobile robot 10 records waypoints at intermittent times when themobile robot 10 is moving. FIG. 41 illustrates an embodiment of awaypoint routine. At step 2101, the routine receives the values forvariables min_dist (the minimum distance by which successive waypointsshould be separated), wait_interval (the period of time the routineshould wait before recording a next waypoint) and pres_coord (thepresent coordinates of the mobile robot 10, as provided by a positionreckoning system), and step 2102 initializes several variables, settinginit_time (the initial timestamp) and pres_time (the current time of thepresent execution cycle) to zero, and prev_coord (the coordinatesascertained for the previous execution cycle) and pres_coord (thecurrently ascertained coordinates of the mobile robot 10) to zero, aswell.

It is determined at step 2103 whether the robot is moving and, if not,the process loops back to step 2103. Otherwise, step 2104 gets thecurrent time (such as from a clock or cycle counter) and stores it tothe variable pres_time. It is then determined at step 2105 whethersufficient time has passed since the initial time and, if not, theprocess returns to step 2103. If sufficient time has passed, then step2106 assigns the value of pres_time to the variable init_time; step 2107ascertains the present coordinates of the mobile robot 10 and storesthem to the variable pres_coord; and step 2108 calculates the distancebetween the mobile robot's current position and the position of themobile robot 10 ascertained at the immediately previous cycle.

If step 2109 determines that not enough distance has been traversedsince the previous cycle, then the process returns to step 2103.Otherwise, step 2110 appends the values of pres_coord (as a positionalrecord) and pres_time (as the corresponding timestamp) to the list ofrecorded waypoints; step 2111 sets the value of prev_coord to the samevalue as pres_coord; and step 2112 updates the variable wait_interval,if necessary or appropriate, before returning to step 2103.

Accordingly, the waypoint routine maintains a list of recorded waypointsseparated by at least minimum permitted differences in time anddistance. The retro traverse behavior can then utilize the list ofrecorded waypoints to generate a return path interconnecting thewaypoints, in reverse order of timestamps.

FIG. 42 illustrates an embodiment of a method for performing a retrotraverse behavior. At step 2201, it is checked whether the behavior isactive and, if so, the behavior proceeds to step 2202 (otherwise loopingback to step 2201). Step 2202 sets the values of retro_start andprev-retro_start to zero; step 2203 erases any previously usedwaypoints; and step 2204 ascertains the current position of the mobilerobot 10 and the current time, which are prepended to the list ofrecorded waypoints.

At step 2205 it is determined whether a control signal has been properlyreceived. If so, then step 2212 proceeds to navigate the robot based onthe instructions received from the operator. Otherwise, step 2206 setsthe value of prev_retro_start to retro_start, and prev_retro_end toretro_end; step 2207 sets the value of retro_start_time to the currenttime; and step 2208 navigates the mobile robot 10 toward the nextprevious waypoint retrieved from the list of recorded waypoints for oneexecution cycle. If step 2209 determines that communication has not beenrestored, the behavior returns to step 2208 and continues navigatingtoward the waypoint; otherwise, step 2210 sets retro_end_time to thecurrent time and step 2211 inserts a new entry (comprising the values ofretro_start_time and retro_end_time) into a list of retro traverseintervals before proceeding to step 2212.

By maintaining a list of previously-performed retro traverses (forexample, by recording a list of start/end time pairs for each period oftime the retro traverse behavior is activated and deactivated), theretro traverse behavior can ignore any waypoints that are recordedduring retro traverse operation, as these are spurious for future retrotraverse purposes. That is, after the mobile robot 10 has finished aretro traverse, it records the range of timestamps on the points itretraced and that it created on its path back. On its next retrotraverse, it may ignore those points.

An embodiment of remote control operation of the mobile robot 10 in anurban combat zone is shown in FIG. 43. An operator 5 is positionedwithin a sandbag-enclosed bunker 9012 adjacent a roadway. The mobilerobot 10 proceeds out from the bunker 9012, under control of thenavigation commands transmitted, preferably wirelessly, by the operator.As shown by the curved dotted line, the mobile robot 10 then traverses apath between various buildings 9011.

At various times during navigation of the mobile robot 10, waypoints Athrough J are recorded. Each recorded waypoint includes informationregarding the position of the mobile robot and a timestamp indicatingwhen the position was sampled. The waypoints may be recorded in theelectronic memory of the mobile robot 10 in a suitable data structure(e.g., as a doubly-linked, indexed list, sorted chronologically bytimestamp) to permit forward and reverse list traversal as well asindexed access to the waypoints, for example.

As the mobile robot 10 proceeds further away from the operator, or whenan obstacle such as the buildings 9011 sufficiently impede wirelesscommunication, the mobile robot 10 may fail to receive the controlsignal transmitted by the operator. Therefore, as an example of apersistent autonomous behavior, the retro traverse behavior may beactivated by the robot 10 when it determines that communication is lost.

Another embodiment of a retro traverse behavior is illustrated in FIG.44A, in which the robot traverses either forward or backward along asingle line 2300. First the mobile robot 10 proceeds out along the line2300 during a first outbound leg 2301. In this case, the waypointroutine records waypoints A and C at positions x=3 and 7. When themobile robot 10 starts retro traversing, it uses these waypoints becauseno previous retro traverse has yet been performed.

In the embodiment of FIG. 44A, the first outward leg 2301 stops justafter t=8 (at which time the mobile robot 10 may have lost radio contactwith the operator or received instructions to stop, inter alia). Thefirst retro traverse leg 2302 then begins at t=8.1 and continues untilt=12, at which time the mobile robot 10 stops retro traversing andresumes outbound traversal along the second outbound leg 2303 (e.g.,after regaining communications with the operator). During the firstretro traverse leg 2302, the mobile robot 10 again travels over points Band A, but does not proceed all the way back to t=0. Also during thefirst retro traverse leg 2302, the waypoint routine generated waypointsat t=9 and t=11.

So the retro traverse interval t=8.1 to 12, representing the start time(t=8.1) and end time (t=12) of the retro traverse leg 2302 is added tothe list of retro traverse intervals, and any waypoints having atimestamp within this range (in this case, the waypoints at t=9, 11) areexcluded on any subsequent retro traverse.

FIG. 44B illustrates an embodiment of the invention that continues fromthe example shown in FIG. 44A. The mobile robot 10 proceeds along thesecond outbound leg 2303 until t=18, when retro traverse is activatedagain. When this second retro traverse leg 2304 starts, the retrotraverse behavior retrieves the list of waypoints having timestampst=17, 11, 9, 7, 3, 0.

From the list of waypoints, the behavior removes from consideration allrecorded waypoints having a timestamp within the interval t=8.1 to 12,resulting in a pruned list t=17 (corresponding to C), t=7 (correspondingto B), t=3 (corresponding to A) and t=0 (an implicit, unnamed timestampcorresponding to the beginning of the robot's movement). This prunedlist corresponds to the desired straight path back to the beginning ofthe journey. Following the second retro traverse leg 2304 ending att=26, a second retro traverse interval t=18 to 26 is appended to thelist of recorded retro traverse intervals (resulting in a list ofintervals comprising the two entries [8.1, 12] and [18, 26]) and thethird outbound leg 2305 then starts (resulting in a third waypoint Drecorded at t=36).

If a third retro traverse leg (not shown) were to start, it wouldaccordingly ignore all waypoints with timestamps within the intervals8.1 to 12 and 18 to 26.

To ensure smooth navigation and avoid abrupt veering or swerving in thevicinity of corner points along an intended path of travel, the mobilerobot 10 may base its navigation on a lookahead vector. A lookaheadvector can be defined in the following way: a starting point lies at theclosest point on the path to the mobile robot 10, and an ending point isa point farther along the path that is either at a maximum distanceaway, or at a shorter distance as determined by the curvature of thepath and/or other factors. For example, the mobile robot 10 maycontinuously drive toward a virtual point approximately 1 meter in frontof it along the intended path. In some implementations, the distancethat the mobile robot 10 looks ahead may be variable, depending upon thegeometry of the lookahead vector.

In addition, rather than always manipulating the x-y coordinates ofpoints directly, navigation of the mobile robot 10 may utilize aline-segment abstraction of the intended path. First, when retrotraversing, the return path can be represented as a set of piecewisecontinuous, conjoining line segments rather than a set of points. Themobile robot 10 may perform most of its calculations in terms of thetangent and perpendicular to the line segment the mobile robot 10 istraversing instead of based on the vector difference to the nextwaypoint. Accordingly, the mobile robot 10 may reduce or eliminate sharpturning when it approaches waypoints conjoining two path line segmentsat acute angles.

Secondly, once the robot has pre-computed the tangents and lengths ofthe line segments, a point can be expressed as a distance along thepath. For example, letting λ represent the tangent unit vector to thei^(th) line segment, then a point r with path length l has a position

$r = {\sum\limits_{i = 0}^{n}{a_{i}\lambda}}$

where a_(i) represents the length of the i^(th) segment for i=0 to n-1and

$a_{n} = {l - {\sum\limits_{i = 0}^{n - 1}{a_{i}.}}}$

Further, the retro traverse behavior may implement a predetermined cycleof calculations to follow a return path:

Determine on which line segment the robot is currently traversing;

Calculate the end of the lookahead vector; and

Calculate motion commands.

The calculations may be done in the listed order during a cycle of thebehavior system because the mobile robot 10 moves after all of thecalculations have been completed.

The retro traverse behavior may use a radius of interception todetermine whether the mobile robot 10 has reached a waypoint, or aperpendicular plane to determine when the mobile robot 10 has passed awaypoint. Preferably, however, the mobile robot 10 keeps track of whichline segment of the return path it is traversing. Since the lookaheadvector keeps track of the local area that the robot's motion is basedon, the only line segments of the retro traverse path that the robotneeds to consider are those spanned by the lookahead vector. The retrotraverse behavior then determines the closest of these line segments andsets that as its reference.

FIG. 45A illustrates an embodiment of the invention where the lookaheadvector 2410 extends from the mobile robot 10 along a linear return pathincluding a first line segment 2401 and second line segment 2402interconnecting waypoints A, B and C. The mobile robot 10 computes itsdistance to all the line segments between the beginning and the end ofthe lookahead vector 2410. The line segment closest to the mobile robot10 is the one it associates with. In the embodiment of FIG. 45A, therobot associates to the first line segment 2401 via the perpendicularline 2411.

In an embodiment illustrated in FIG. 45B, third and fourth line segments2403, 2404 interconnecting waypoints D, E and F, form an angle withwaypoint E as the corner. Here, on the previous iteration, the mobilerobot 10 determined it was closest to the third line segment 2403, andthus the lookahead vector 2410 starts there for the present cycle.However this time it finds that it is closest to the fourth line segment2404, meaning it has passed waypoint E.

FIG. 45C illustrates a situation similar to the arrangement of FIG. 45B;however, in FIG. 45C, the lookahead vector—which is rooted in the fifthline segment 2405—does not extend all the way out to the closest pointon the sixth line segment 2406. In this case, the mobile robot 10 shouldnot associate with the sixth line segment 2406 because then the mobilerobot 10 would short cut the desired path. Accordingly, the lookaheadvector preferably gets shortened in order to avoid taking short cutsthat bypass waypoints. To achieve proper paths without shortcutting, theretro traverse behavior does not accept any line segments for which theclosest point to the mobile robot 10 is beyond the end of the lookaheadvector.

In the embodiment of FIG. 45C, the mobile robot 10 stays on the fifthline segment 2405 despite it being farther away than the sixth linesegment 2406. Once the mobile robot 10 has determined which line segmentit is on, it calculates the closest point to the mobile robot 10 on thatline segment. This point is then used as the origin of the lookaheadvector for the subsequent iteration.

After determining the beginning of the lookahead vector, the retrotraverse behavior next determines where the end of the lookahead vectoris. Referring to an embodiment of the invention illustrated FIGS. 46Athrough 46D, the lookahead vector 2510 may have a length established bydefault to a predetermined value (e.g., one meter long). However, theretro traverse behavior may be implemented so as to ensure that themobile robot 10 drives at least within a maximum permitted distance ofeach waypoint. If the lookahead vector 2510 were to always stay at itsfull default length, the mobile robot 10 might traverse a route with allthe curves excessively smoothed out in some circumstances.

In view of this, the embodiment of FIGS. 46A through 46D demonstrate asystem for determining when and how to shorten the lookahead vector 2510to keep the mobile robot 10 aligned with the intended path. FIG. 46Ashows a straight-line path comprising first and second line segments2501, 2502. In this case, the path of mobile robot 10 passes well withinthe permitted distance from waypoint A and accordingly, the lookaheadvector 2510 may remain at its full default length.

In FIG. 46B, the mobile robot 10 has moved farther along the path to asection where it angles slightly at waypoint E between the third linesegment 2503 and fourth line segment 2504. Because the mobile robot 10will attempt to drive toward the end of the lookahead vector 2510, theappropriate approximation of the mobile robot's path is the vectorextending from the mobile robot 10 to the end of the lookahead vector2510.

To ascertain whether the mobile robot's route will lie within thepermitted distance from a waypoint, the retro traverse behavior checkswhether the perpendicular distance from a waypoint to is less than themaximum permitted distance (which may be a predetermined, constantvalue-such as one meter, for example). The mobile robot 10 repeats thischeck for every waypoint disposed orthogonally to the lookahead vector(i.e., waypoints for which there exists an orthogonal projection ontothe lookahead vector). Alternatively, the mobile robot 10 may repeat thedistance check for every waypoint that is associated with any of theretro traversal path line segments intersected by the lookahead vector2510, to simplify the calculation of whether a waypoint “lies along” thelookahead vector 2510. In the example shown in FIG. 46B, the distance iswithin the permitted range; therefore, the lookahead vector 2510 extendsto its full length.

FIG. 46C shows a similar situation; however, the full-length lookaheadvector 2510 does not lead to a path that is within the permitteddistance of one of the waypoints (waypoint I) that projects orthogonallyonto the lookahead vector 2510. The mobile robot 10 therefore sets theend of the lookahead vector 2510 (which will be used in the subsequentcycle) to be the mean of the current end point and the end point of theprevious lookahead vector 2511 used in the preceding cycle of thebehavior. The retro traverse behavior running on the mobile robot 10will continue to decrement the length of the lookahead vector 2510 forseveral iterations in a similar manner until it either finds anacceptable end point or performs a maximum threshold number ofiterations without success. Because the end point of the lookaheadvector 2510 should always be on a line segment in the intended path, themean of the old and new end points are preferably calculated in terms ofthe respective path lengths of the two and then transformed into x-ycoordinates, rather than averaging the x-y coordinates of the twopoints.

FIG. 46D illustrates a situation with a sharp angle between the seventhand eighth line segments 2507, 2508. The waypoint K does not projectorthogonally onto the lookahead vector 2510 shown in FIG. 46D.Accordingly, the retro traverse behavior preferably ensures that theclosest point is actually within, to obviate this situation.

FIG. 47 illustrates an embodiment of a relationship between two outputvalues, v_rotate and v_translate, that may be issued by the retrotraverse behavior. The translational (v_translate) and rotational speeds(v_rotate) are calculated based on the angle by which the mobile robot10 needs to turn to be heading toward at the end of the lookaheadvector. The rotational speed may be determined as a PID loop on thefunction v_rotate shown in FIG. 47, for example. The functioncharacteristics may be adjusted to ensure the mobile robot 10 does notovershoot waypoints.

Also, in another embodiment, there are three different modes in whichthe mobile robot 10 can operate:

“always drive forward;”

“always drive backward;” or

“drive in which ever direction requires the least rotation.”

For “always drive forward,” the speeds are calculated based on the anglebetween the mobile robot's heading and the direction to the end of thelookahead vector. For “always drive backward,” they are based on θ₂, andthe translational speed is multiplied by −1. For “driving the directionof least rotation,” when θ in between θ₁ and θ₂ then the mobile robot 10drives forward; otherwise, it drives backwards.

Retro traverse can be implemented in the following exemplary manners:

the robot will either track odometry and determine position based onthat;

will maintain a global map and place the coordinates within a globalmap;

will maintain a far off destination point within a global map and adjustits heading to move towards that point;

will use some sort of navigation point (i.e. GPS, or other satellite orlandmark easily detected from most points within the environment); or

will communicate with navigation beacon points (signal repeaters, etc.)and use those to determine position within the environment.

Alternative methods of implementing retro traverse include: (1)following a reduction in chemical scent, or following a chemical scent;or (2) following a trail left by the robot—i.e. a fiber optic cable, aline of spray paint, setting a destination point in a global map andtraveling towards that destination point.

Two alternative methods of implementing retro traverse include:

Collecting odometric data and using it to calculate the return path;

-   -   1. Example Data—heading and approximate distance of travel for        each stage of retro traverse.

GPS waypoint collection

-   -   1. GPS approximations can be collected.    -   2. Tie these approximations to the odometry data.    -   3. Use Kalman Filter based algorithms to provide confidence in        the return path.

Self-Righting

Self-righting behaviors can also be persistent, in a sense that it maybe running in the background to right the robot if it is up-ended.Robots traveling over very rough terrain or through opposing fire canend up flipped on their sides or even upside down. Self rightingbehavior allows the remote vehicle to turn itself back over and onto itstracks so it can continue with its mission objective or return back tothe operator, as desired. When self righting, the robot senses itsorientation and determines a strategy for turning itself upright. Therobot will perform a progression of increasingly complex arm and flippermotions until it has levered itself back onto its tracks.

Self righting has two modes. In the first mode, it will be autonomouslyinitiated when the robot detects that it has flipped upside down. In thesecond mode, the operator explicitly commands the robot to start or stopself righting. The advantage of enabling persisent autonomous selfrighting is that should communications be degraded because the antennaeare beneath the unit to the point where the operator cannot directlycommand it, the robot can rescue itself without explicit direction, andwithout the need for hands-on human intervention.

Semi-Ballistic Behaviors

Semi-ballistic behaviors allow the operator to manually operate theremote vehicle. Semi-ballistic behaviors can quit when certain actuatorsare actuated such as stop a speed boost behavior when the operatoractuates a stop button or switch, the drive control, or a quick brake.

Speed Boost and Quick Brake

In an embodiment of the invention, activating speed boost or quick brakebehavior allows the operator to quickly increase or decrease the currentdrive speed of the mobile robot 10. Once activated, the mobile robot 10will continue to drive with the new drive speed until a new behavior,action, or event occurs. An example of this is the execution of thespeed boost behavior while the mobile robot 10 is driving forward at acurrent drive speed. Upon execution, the mobile robot 10 then drivesforward at a speed equivalent to the current drive speed increased by apreset speed value stored in memory.

FIGS. 48 and 49 illustrate an embodiment of speed boost and quick brakebehaviors. These behaviors are initiated by activating a switch orbutton of the control system described above. Activating the button orswitch multiple times in a row will result in multiple and successiveexecutions of the chosen behavior. The end result is a new drive speedequivalent to the current drive speed increased or decreased by a factorof the preset speed value multiplied by the number of times the buttonor switch was activated.

The speed boost behavior stores the current drive speed 8001 and thecurrent drive heading 8002. The behavior then calculates a new drivespeed value by increasing the current drive speed value by a factorequivalent to a preset speed value 8004 stored in memory 1125. A speedcheck 8006 is done to ensure that the new drive speed is compatible withbehaviors or routines that may be active on the mobile robot 10. If thespeed check 8006 allows for the new drive speed, the mobile robot 10drives forward at the new drive speed 8010 and the speed boost behaviorends 8012. Otherwise, if the speed check 8006 does not allow for the newdrive speed, then the mobile robot 10 drives forward at the currentdrive speed 8008 and the speed boost behavior ends 8012.

The quick brake behavior embodiment shown in FIG. 49 is similar to thespeed boost behavior embodiment in that it stores the current drivespeed 8014 and the current drive heading 8016 and performs a speed check8020 once the new drive speed is calculated. The quick brake behaviordiffers in that the new drive speed is calculated by decreasing thecurrent drive speed by a factor equivalent to the preset speed value8020. Like the speed boost behavior, if the new drive speed is allowed,then the mobile robot 10 drives forward at the new drive speed 8024 andthe quick brake behavior ends 8026. Alternatively, if the new drivespeed is not allowed, then the mobile robot 10 drives forward at thecurrent drive speed 8020 and the quick brake behavior ends 8026.

Alternate embodiments of speed boost and quick brake may include:

A speed boost behavior that sets a zone of acceptable speeds that isgreater than the normal zone (e.g., typically the robot can drive at aspeed between 2 and 20 MPH, but with speed boost it can drive between 15and 50 MPH);

A speed boost behavior that provides a quick boost of speed for a periodof time—then returns to the previous drive speed;

A quick brake that lowers the zone of acceptable speeds (e.g., zone isnow 0 to 5 MPH from 2 to 20 MPH); and/or

A quick brake that for a period of time quickly reduces the speed of therobot, then returns to the previous drive speed after the period oftime.

Cruise Control

A cruise control behavior receives information from the control systemregarding an intended constant speed and heading for the mobile robot10. In an embodiment of the invention, the information sent from thecontrol system includes an acceleration value and a rotational velocity,both of which are used by the mobile robot 10 to determine a drivevelocity and heading. The cruise control behavior allows the operator todrive the robot 10 for a distance without necessary intervention by theoperator. In an embodiment of the invention, the operator uses a leftand right joystick or puck of the control system to control the robot'smovement. In this embodiment, the left joystick or puck can be dedicatedto the cruise control behavior such that when the left joystick or puckis actuated, the cruise control behavior commences, and when the rightjoystick or puck is actuated, the cruise control behavior halts.Alternatively, the cruise control behavior could commence following theactuation of a button or other actuator of the control system.Alternatively, a third joystick or puck may be included in the controlsystem that is dedicated to cruise control.

In an embodiment of the invention utilizing pucks, each puck has theability to rotate about a vertical axis, translate forward and backwardabout a horizontal axis, and tilt away from the vertical axis.Furthermore, when the puck is translated, rotated or tilted, it is themovements correspond to different movements of the robot. In particular,driving the robot in a forward or backward direction is preferablycontrolled by the translation of the puck about a horizontal axis,alteration of the robot's heading is controlled by the rotation of thepuck about a vertical axis, and actuation of the flippers included onthe robot are controlled by tilting the pucks. An example of themovement of a robot in response to puck movement is one in which thepuck is rotated about the vertical axis 30° in a clockwise direction,and the puck is moved forward a distance of a half inch. In response, arobot at rest will adjust its heading by turning 30° in a clockwisedirection, and driving forward at a velocity equivalent to apre-determined value associated with movement of the puck a half inch.Should the puck be tilted to the right 15° from the normal, the robot'sflippers would respond by rotating towards the ground an angleequivalent to 15°.

FIG. 50 illustrates an embodiment of a cruise control routine 3200included within a cruise control behavior. When in control of itscorresponding actuators, the cruise control behavior executes the cruisecontrol routine 3200, which commences by scanning for a new set ofcruise commands 3212 from the operator. Should the routine sense a newset of cruise commands, the routine inputs the commands as an absoluteheading 3215. There may be a time lag between when the robot's camerasrecord video information and the time that such information is displayedto the operator. If the robot 10 is moving at a particular speed andparticular heading, and a new heading and/or speed is chosen by theoperator and sent to the robot, the robot will have moved a certaindistance during the time between when the robot's camera detected theimage and when image was displayed to the operator. The latency of thesystem can cause discrepancies when sending the robot cruise commands.

In an embodiment of the invention, to eliminate the possibility of thesediscrepancies, the operator sends the robot 10 an absolute heading andvelocity. When the robot 10 receives the absolute heading and velocity,the robot then calculates its new heading and velocity using theabsolute heading and velocity and the positional and velocity values atthe time the robot's camera detected the image, rather than the currentreal-time positional and velocity values. Upon calculating the newtravel velocity and heading, the robot 10 uses real-time positional andvelocity values to calculate a new travel vector 3218.

Once a travel vector is calculated 3218, the robot will then drive atthe specified velocity using the specified heading 3201. While driving,the cruise routine gathers real-time positional and velocity values fromthe sensors 3203 and compares these values to the chosen travel vector3206. Should there be a significant difference between the currenttravel vector and the chosen travel vector, the routine will instructthe robot 10 to adjust its heading and velocity 3221 using past odometryvalues. Otherwise, if there is little difference between the currenttravel vector and the chosen travel vector, the routine will instructthe robot 10 to continue driving 3201.

Further illustrative of an embodiment of cruise control, FIGS. 51A and51B display a robot 3444 that responds to new heading commands to changedirection. The robot 3444 moves forward in a particular direction 3440.Once the operator retrieves video feedback of the robot's position, therobot's position has changed from its position at the time the videoinformation was captured 3446 to its current position 3444. Thus, therobot has continued along its current path 3440 during the time betweenwhen the robot collects video information of its position at that time3446 and the time when the robot receives new heading commands from theoperator. When the operator sends the heading information to the robot10, the heading information 3442 is relative to the robot's previousposition 3446. FIG. 51B shows how the robot uses the heading 3442generated in relation to the robot's previous position 3446 to determinea new heading 3452 calculated in relation to the robot's currentposition 3444.

FIG. 52 illustrates an embodiment of a flow of information in the cruisecontrol behavior. Input from the control system is received andprocessed to produce an updated current intended heading and speedθ_(n), v_(n). In the equations displayed, θ_(n-1) is the intendedheading of the preceding cycle, t_(n) is the time of the current cycle,t_(n-1) is the time of the preceding cycle, θ (t_(n)-t_(n-1)) is theangular difference between the heading of the current cycle and theheading of the preceding cycle, v_(n-1) is the intended speed of thepreceding cycle, and (v_(n)-v_(n-1)) is the difference between the speedof the current cycle and the speed of the preceding cycle.

Simultaneously, input from position reckoning systems (such as acompass, IMU, or GPS) are fed to a motion tracking system, which updatesthe reckoned actual heading and speed. The reckoned actual heading andspeed of the mobile robot 10, as well as the updated intended headingand speed, are passed to a comparator, which generates an appropriateoutput (such as turn rate and drive motor current) to control the drivesystem.

Activation of the cruise control behavior includes first actuating anactuator of the control system. As discussed above, the actuator may bea puck, button, lever, soft button, or any other actuator that initiatesthe cruise control behavior. FIG. 53 illustrates an embodiment of aroutine carried out by the control system (using a puck for cruisecontrol activation) to generate cruise control commands. The routinescans a puck designated for activating and controlling the cruisecontrol behavior 3251. Upon detecting a change in the position of thepuck 3253, the routine determines whether the change included a rotationof the puck about a vertical axis 3256. If not, the routine willcontinue to scan the puck's position. If the change included a rotationof the puck about a vertical axis 3256, the routine calculates arotational velocity proportional to the rotation of the puck andindicative of the direction the puck was rotated 3259, and the controlsystem sends the new drive heading to the robot 10, where the heading isrelayed to the cruise control behavior.

The routine then determines whether or not the puck was translated abouta horizontal axis 3265. If this has occurred, the routine calculates anacceleration/deceleration command 3268 representative of the puck'smovement, and the control system sends the acceleration/decelerationcommand 3271 to the robot 10 where the acceleration/deceleration commandis relayed to the cruise control behavior. In the illustratedembodiment, if the routine detects a tilting of the puck 3274, theroutine exits 3277 because such a movement of the puck indicates flippermovement which is controlled by a behavior other than the cruisecontrol—activation of another behavior causes cruise control to halt. Ifthe routine does not detect a tilting of the puck 3274, the routinecontinues to scan the puck's position 3251.

FIG. 54 illustrates an embodiment of the interaction between the cruisecontrol behavior and other behaviors installed on the robot's singleboard computer. When the cruise control behavior has control of therobot's actuators, it executes its cruise routine 3301. However, whenthe coordinator indicates that another behavior has been activated 3303and that behavior has a higher priority 3306 than the cruise controlbehavior, the cruise control behavior is halted and the cruise routineexited 3318. Otherwise, if the coordinator does not indicate thatanother behavior has been activated 3303, or if a behavior has beenactivated but that behavior does not have a priority 3306 greater thanthe cruise control behavior, the cruise control routine will continue toexecute 3301. In an embodiment of the invention, when a behavior with ahigher priority than cruise control is activated, the coordinator checkswhether this behavior is the obstacle avoidance behavior 3309, and iftrue, allows the obstacle avoidance behavior to have control of theactuators without halting the cruise control behavior. Otherwise, if theobstacle avoidance behavior is not identified and the behavior has ahigher priority than the cruise control behavior, the cruise controlbehavior will exit the cruise routine and halt 3318.

Should the obstacle avoidance behavior gain control of the actuators, anobstacle avoidable routine is executed 3312 by the obstacle avoidancebehavior. Once the obstacle avoidance behavior is executed and exited,cruise control may regain control of the actuators 3321. Once in controlof the actuators, the cruise control will pick up where it left off andbegin executing the cruise control routine 3301. Within the cruiseroutine 3200 (see FIG. 50), a check is made of the robot's real-timetravel vector 3203. Since the obstacle avoidance routine caused therobot to veer away from the chosen travel vector, the cruise controlroutine will detect the change in travel vector and correct the robot'sheading and velocity 3221 using past odometry values so that the robotreturns to the chosen travel vector.

An embodiment of the interaction between the cruise control behavior andthe obstacle avoidance behavior is illustrated in FIGS. 55A-55D.Obstacle avoidance can be a persistent behavior, but is discussed herebased on its interactions with cruise control. FIG. 55A shows therobot's 3458 movement along the chosen travel vector 3456 dictated bythe cruise control behavior, where the vector 3456 points the robottoward an obstacle 3454. FIG. 55B illustrates the robot's response tothe obstacle 3454 by commanding the robot to drive to a position 3460not included within the chosen travel vector, which is the result of anavoidance travel vector 3462 instituted by the obstacle avoidancebehavior to cause the robot 10 to avoid the obstacle 3454.

Once the obstacle 3454 is avoided, the cruise control behaviorre-assumes control of the actuators and, as shown in FIG. 55C, begins toadjust the robot's direction of travel so that the robot returns to apath included within the chosen travel vector 3456. To do this, thecruise control behavior alters the robot's heading so that the robotdrives along a path included within a translational vector 3462calculated to cause the robot 3460 to return to the chosen travel vector3456. FIG. 55D displays the final effect of the translational vector3462. The robot 3458 moves from a path included within the avoidancetravel vector 3462 to a path within the chosen travel vector 3456.

The obstacle avoidance behavior can include an embodiment of an obstacleavoidance routine as illustrated in FIG. 56. Once an obstacle isdetected 3520 and the obstacle avoidance behavior has retained controlof the actuators, the obstacle avoidance routine begins to execute. Theroutine first inputs camera video output of the obstacle detected 3522and uses the camera's resolution to determine the dimensions of theobstacle. To ensure proper clearance, the routine bloats the obstacle bya pre-determined value so that an avoidance vector can be calculated3518. The avoidance vector allows the robot 10 to drive along a paththat avoids the obstacle 3528. As the robot 10 drives forward 3528, theroutine continually checks for obstacles 3530. If an obstacle isdetected, the robot 10 then inputs the video image of the obstacle 3522,determines its dimensions 3524, bloats the obstacle 3526 and calculatesa new avoidance vector 3518. These steps occur until no obstacle isdetected, at which point the obstacle avoidance routine is exited 3532and the cruise control behavior regains control of the actuators.

In an embodiment of the invention, the cruise control behavior assumesthat the robot is moving at a velocity of 0 m/s, and considers therobot's position to be the normal position. Subsequent rotationalvelocities and accelerations/decelerations are an alteration of therobot's 0 m/s velocity and normal position. Alternatively, the cruisecontrol behavior could include cruise routines that allow foracceleration and/or deceleration of a robot with a velocity other than 0m/s. In such an embodiment, an additional actuator may be included inthe control system so that the user can control activation of cruisecontrol with an actuator separate from the puck.

Other possible features of the cruise control behavior include fail safeconditions that cause the cruise control behavior to halt. Theseconditions include: (1) actuating brakes included within the drivesystem; (2) actuating a button, switch, puck, or other input device notdesignated to control the cruise control behavior; (3) depressing a stopactuator included of the control system; (4) changing the drive mode; or(5) dropping communication between the control system and the robot 10.Additionally, there is a maximum speed at which the robot can go and therobot is configured not to drive at a speed higher than the maximumspeed.

Alternative embodiments of the implementation include:

Setting a point far in the distance and driving toward that point sothat when a behavior like obstacle detection interrupts, the cruisecontrol behavior can do one of calculating a path from the robot'scurrent position back to the original cruise path and calculating a newpath from the robot's current position to the destination point

Tracking odometry and adjusting the robot's current path using atranslational vector calculated from the odometry values so that whenobstacle detect interrupts, the cruise control behavior calculates atranslational vector from the past odometry values and applies thevector to the robot's current path—so that the robot will return to thecruise path.

Set a start waypoint and end waypoint when a behavior like odometryinterrupts cruise, meaning that two waypoints are stored while the robotis still on the cruise control path and at the point in time whenobstacle detection is initiated, the first waypoint being representativeof the robot's position when obstacle detect interrupts an the secondwaypoint being representative of a point much farther down the path fromthe first waypoint (far enough that the point will exist at a positionbeyond the obstacle). After obstacle detection finishes, the cruisecontrol behavior uses the two waypoints to calculate a path back to theoriginal cruise control path.

In an embodiment of the invention, the cruise control behavior sends an“operator attention required” alert to the operator. Alert conditionsmay include:

Hard bump to the manipulator arm, indicating contact with a solidobject.

Repeated drifting off course, indicating uneven ground.

Tilt or roll approaching tip-over limits.

Increased motor torque indicating the presence of an obstruction.

Time-out situations to prevent over-travel.

Other embodiments of the cruise control behavior include a cruisebehavior that can be used while drive is in control, the user actuatinga cruise control button of the control system. The cruise controlbehavior can also be activated such that the robot will cruise for apredetermined period of time, or a predetermined distance.Alternatively, the cruise control behavior could include a hybrid wheresuch an action would happen unless the user instructs the normal cruiseto take over indefinitely.

Obstacle Avoidance

An embodiment of an obstacle avoidance behavior is described above. Waysof implementing the obstacle avoidance behavior include:

Path Planning—the robot detects obstacles & bloats them, then calculatesa path around the obstacle. Path planning may be carried out while therobot is traversing the path to ensure that the robot remains on thepath.

Continuous obstacle detection where there are obstacle detection sensorsinstalled along the sides of the robot. The robot turns a predeterminedangle and moves a predetermined distance in response to a forwardobstacle detection. Once the forward sensor no longer detects theobstacle and if the side sensors detect the obstacle, obstacle detectmoves forward until the side sensors no longer detect the obstacle.

1. A system for allowing an operator to switch between remote vehicletele-operation and one or more remote vehicle autonomous behaviors,comprising: an operator control system receiving input from the operatorincluding instructions for the remote vehicle to execute an autonomousbehavior; a control system on the remote vehicle for receiving theinstructions to execute an autonomous behavior from the operator controlsystem and comprising an arbiter wherein the autonomous behavior sends avote to the arbiter requesting control of one or more actuators on theremote vehicle configured to perform the autonomous behavior and, if thevoting autonomous behavior has a higher priority than a behaviorcurrently in control of the one or more actuators the autonomousbehavior executes.
 2. The system of claim 1, wherein the remote vehicleexecutes the autonomous behavior if permitted.
 3. The system of claim 2,wherein the autonomous behavior is not permitted if one or more of theremote vehicle's position within its environment, a current internalstate of the remote vehicle, a current operational behavior of theremote vehicle, or the remote vehicle's environment are incompatiblewith the autonomous behavior. 4-5. (canceled)
 6. The system of claim 1,wherein the autonomous behavior comprises one a ballistic behavior, asemi-ballistic behavior, and a persistent behavior.
 7. The system ofclaim 6, wherein the ballistic behavior comprises of stair climbing, apreset action, click-to-drive, click-to-grip, a preconfigured pose,retro traverse, self-righting, and autonomous flipper.
 8. The system ofclaim 6, wherein the semi-ballistic behavior comprises of quick brake,speed boost, and cruise control.
 9. The system of claim 6, wherein thepersistent behavior comprises of retro traverse, self righting, obstacleavoidance, and autonomous flippers.
 10. A method for switching betweenremote vehicle tele-operation and one or more remote vehicle autonomousbehaviors, comprising: inputting instructions for a remote vehicle toexecute an autonomous behavior; determining whether one or more of theremote vehicle's position within its environment, a current internalstate of the remote vehicle, a current operational behavior of theremote vehicle, and the remote vehicle's environment are incompatiblewith the autonomous behavior; allowing the autonomous behavior to send avote to an arbiter when it is determined that one or more of the remotevehicle's position within its environment, the current internal state ofthe remote vehicle, the current operational behavior on the remotevehicle, and the remote vehicle's environment are compatible with theautonomous behavior, wherein a vote to the arbiter requests control ofone or more actuators on the remote vehicle configured to perform theautonomous behavior, and executing the autonomous behavior if the votingautonomous behavior has a higher priority than a behavior currently incontrol of the one or more actuators.
 11. (canceled)
 12. The system ofclaim 10, wherein the autonomous behavior comprises of a ballisticbehavior, a semi-ballistic behavior, and a persistent behavior.
 13. Thesystem of claim 12, wherein the ballistic behavior comprises one or moreof stair climbing, a preset action, click-to-drive, click-to-grip, apreconfigured pose, retro traverse, self-righting, and autonomousflipper.
 14. The system of claim 12, wherein the semi-ballistic behaviorcomprises one of quick brake, speed boost, and cruise control.
 15. Thesystem of claim 12, wherein the persistent behavior comprises one ofretro traverse, self righting, obstacle avoidance, and autonomousflippers. 16-18. (canceled)
 19. The system of claim 32, wherein thecontrol system comprises an arbiter, and wherein the autonomous behaviorsends a vote to the arbiter requesting control of one or more actuatorson the remote vehicle configured to perform the autonomous behavior. 20.The system of claim 19, wherein, if the voting autonomous behavior has ahigher priority than a behavior currently in control of the one or moreactuators, the autonomous behavior executes. 21-22. (canceled)
 23. Thesystem of claim 32, wherein the semi-ballistic behavior comprises one ormore of quick brake, speed boost, and cruise control.
 24. The system ofclaim 32, wherein the persistent behavior comprises one of retrotraverse, self righting, obstacle avoidance, and autonomous flippers.25. The system of claim 32, wherein the persistent autonomous behavioris executed continuously, upon input from one or more sensors of theremote vehicle, or upon being activated by another behavior.
 26. Amethod for implementing remote vehicle autonomous behaviors, comprising:inputting instructions for the remote vehicle to execute an autonomousbehavior comprising one of a ballistic a semi-ballistic and a persistentbehavior; evaluating one or more of the remote vehicle's position withinits environment, a current internal state of the remote vehicle, acurrent operational behavior of the remote vehicle, or the remotevehicle's environment are incompatible with the autonomous behavior; andallowing the autonomous behavior to send a vote to an arbiter if theremote vehicle's position within its environment, the current internalstate of the remote vehicle, the current operational behavior on theremote vehicle, or the remote vehicle's environment are compatible withthe autonomous behavior, wherein a vote to the arbiter requests controlof one or more actuators on the remote vehicle necessary configured toperform the autonomous behavior and wherein a ballistic behaviorcomprises one of stair climbing, a preset action, click-to-drive,click-to-grip, a preconfigured pose, retro traverse, self-righting, andautonomous flipper.
 27. The method of claim 26, further comprisingexecuting the autonomous behavior if the voting autonomous behavior hasa higher priority than a behavior currently in control of the one ormore actuators. 28-29. (canceled)
 30. The system of claim 26, whereinthe semi-ballistic behavior comprises one of quick brake, speed boost,and cruise control.
 31. The system of claim 26, wherein the persistentbehavior comprises one of retro traverse, self righting, obstacleavoidance, and autonomous flippers.
 32. A system for allowing anoperator to switch between remote vehicle tele-operation and one or moreremote vehicle autonomous behaviors, comprising: an operator controlsystem receiving input from the operator including instructions for theremote vehicle to execute an autonomous behavior; and a control systemon the remote vehicle for receiving the instructions to execute anautonomous behavior from the operator control system, wherein theautonomous behavior comprises one of a ballistic behavior, asemi-ballistic behavior, and a persistent behavior, and wherein theballistic behavior comprises one of stair climbing, a preset action,click-to-drive, click-to-grip, a preconfigured pose, retro traverse,self-righting, and autonomous flipper.
 33. The system of claim 32,wherein the preconfigured pose comprises one of a prairie dog pose, astowed pose, a driving on a flat surface pose, a driving on a bumpy orangled surface pose, and a stair climbing pose.
 34. A system forimplementing remote vehicle autonomous behaviors, comprising: anoperator control system receiving input from the operator includinginstructions for the remote vehicle to execute an autonomous behaviorcomprising a preconfigured pose; and a control system on the remotevehicle for receiving the instructions to execute the autonomousbehavior from the operator control system, wherein the preconfiguredpose comprises one of a prairie dog pose, a stowed pose, a driving on aflat surface pose, a driving on a bumpy or angled surface pose, and astair climbing pose.